This info does not try to cover what vehicles/equipment you should use to do a given job as cheap as possible. It tries to answer exactly what the cost of owning the vehicle/equipment is, and at what time (if any) you should replace it due to depreciation. This assumes you want to maintain your vehicles as the game intends. Quite a bit of gear can be used just fine in broken state, so if you want to take advantage of that you basically don't have depreciation and can hang onto gear forever and ignore the rest of the info here (though you need to identify which gear doesn't work broke;)
Both vehicles and equipment are stored in the vehicles.xml file in your save game and are handled as the same type of entity. I will just be calling it vehicles below, but I'm pretty sure they are handled the same. The only difference I've noticed as of now, is how fast they get paint damage. A plow that is plowing is getting paint damage considerably quicker than the tractor pulling it. However, their maintenance state seems to be changing at exactly the same pace. When you press buy, I call the price you pay the initial price, which is the listed price in your save game. Any later expenses through customization is part of your total cost for the vehicle, but is ignored by game effects.
The data here is retrieved testing on version 1.2.0.2. I have of course not tested all types of vehicles and equipment doing all types of work in all possible different situations and the like. There are assumptions made that if there's no reason this other piece should be handled differently, it likely isn't.
Purchase cost
This is the obvious part of the cost. While reselling and maintenance don't care about customizations, the added money you used for that of course is included in the total cost for acquiring it in calculations below.
Maintenance cost
Maintenance cost is split into two concepts. The game is tracking the damage a vehicle has in the save game, under <wearable damage="x">, where a value of 0 is perfect condition, full green bar in game and nothing to repair. When totally damaged the value becomes 1. If I state the vehicle is in 80% maintenance condition, the value in the savegame will be 0.2. The first concept, is what is making this damage value go up, and at what speed. The second concept is, given that your vehicle has a given amount of damage, how much will it cost to repair it.
Speed of acquiring damage
I assume that certain actions in the game will add a number to the current damage value, until you reach the cap of 1, and that these actions will add the same regardless of what the current damage value is (unless of course you reached the cap). I've tried to figure out what these actions are and if they add damage at different values.
- Just being "in use" adds damage at a fairly steady pace.
- As far as my limited tests have shown, I have not been able to see a difference in speed, whether a tractor was standing still idling with engine on, or using all it's horsepowers to pull a plow, or whether a plow was actually plowing, or just in raised condition on a tractor turned on. If these actions actually account for different speeds of damage, I have not been able to notice them, and if so they should be small.
- The already existing operation time of the vehicle is a big impact on how fast it gets new damage.
Above is my plot on how damage is applied based on the current operation time of the vehicle. This test was made with a tractor with front weight plowing a field. Tractor, front weight and plow all got damage at equal speeds when at the same operation time, so I could get in 3 points in graph above for each 5 minute test run. There's a cap at 180000 seconds (50 hours), at which the speed of which you acquire damage no longer increases. This equation is simple and fits very well with the data collected, so I'm thinking it is very close to, if not exactly what the game uses.
Cost of repairing acquired damage
Testing this is far simpler as one can just alter state in save game and see what game wants for a repair. Tested that the price scales directly of initial price of the vehicle and maxes out at 9% of the initial price. Note that the curve is bending upwards, indicating that it is more expensive to repair the longer you wait. This equation is simple and fits so well with the game values, that I believe it is 100% correct.
Turning the values around, we can plot the cost of repairing based on how late you repair:
In my opinion this curve should have been different. In the real world, it would be terribly expensive to put your tractor into a repair shop every day to fix it to brand spanking new state. There's no reason the game should reward you for repairing as often as possible. Though it makes sense that it pays of to not wait until stuff starts breaking and put more strain on other parts. But as it is, you can save a lot of money repairing early.
Repaint cost
I've tested that the repaint state does not affect how quick you get damage. Thus, having a botched paint does not make your equipment more expensive to use. In theory I guess they could have made something in poor paint condition perform its task worse in some way, but I very much doubt it. I thus assume paint status only have a visual effect until you try to sell your vehicle. People want to buy stuff looking new, and according to my testing it always pays of to repaint your equipment before selling. For sell price discussed below we thus always assume vehicle is in perfect paint state, and we need to account for the cost of one repaint in the vehicles history.
Same as for maintenance, it is a split between how fast you get paint damage, and the cost of fixing it. I have noticed a plow plowing gets paint damage quicker than the tractor pulling it, so for paint damage, there are some types and/or action differences. However, you get paint damage fairly quickly just by idling too, so fairly likely the paint state is totally botched before you want to sell your gear, if you actually ended up using it. I've also tested that you acquire paint damage at the same rate compared to operation time of the vehicle.
From my test runs, I've seen a few different values. Driving around on tarmac, seems to give the lowest values, of around 0,0000173 paint damage/sec. When I was in the field, a normal value have been twice that, 0,0000346 per second, and for a plow plowing I've seen numbers around 0,0001163, about 6x as fast as driving on tarmac. To simplify, I've just assumed paint damage will be the 0,0000346 value. If we see paint damage being an important part, we can look into more details.
I've put less effort into finding the exact in game formula here, but above you can see trend lines of my example data. To make fitting trend lines, I made one for <=0.2 and one for >=0.2, which seems to cover my test samples well at least. Looks good enough for now. As can be seen, repaint cost caps out at 20% of initial price of the vehicle.
Loss of value when selling
When you no longer want your vehicle you can get some money back from the shop. Important: If you sell at repair shop using customization window, you get 10% more than if you sell through the garage window. So you can save considerably getting there. You also should always repair and repaint before selling as that gives you more money back too, so then you need to get there anyhow. Calculations below assume you sell at repair shop in perfect maintenance and paint condition.
Getting the correct formula for the sell value have proved a bit difficult. It depends on both age and operation time, so it has two variables. I kind of assumed it would be something like <initial price> * <age penalty> * <optime penalty>, and that I thus could track age and optime penalties independently, and then add them together for the total. I haven't found a perfect match, but at least have an approximation that's fairly close.
The effect of operation time only seems to follow a simple linear formula. This I'm guessing is correct. Though the 12% here isn't optime specific, but only an effect of initial sell price being 12% below initial price you bought it for.
For the age effect I have not found a single formula that seems fitting. Split the range into 3 different approximations to keep close to measured values. Up to 7 months there is no degradation beyond the initial 12%. 8-50 months follow trendline above. 50-200 graph below.
And beyond 200 follows the below one here, at least up to 1000. Haven't bothered measuring longer. Not gonna play a farm longer than a man could theoretically work it before having to retire anyhow in real life.
Total consideration
Combining all these calculations, we can calculate monthly cost of ownership. (Fuel usage currently excempted, I know.. Useful to add to compare vs leasing, but assuming fuel usage doesn't go way up due to depreciation, it shouldn't matter much as to when to switch)
Here is an overview of monthly price for a Fendt 1038 Vario tractor. It doesn't really matter what it is, just that you payed $329.000 for it and didn't use extra money customizing it.
The above table can be interpreted like:
The graph shows the monthly cost of ownership, given that you sell it after X months. We see that once you have kept it for 200 months you have paid slightly above $2000 per month and keeping it on a lot longer doesn't reduce this value a lot. We also see that due to the cap of how fast maintenance cost is added, it keeps on getting slightly cheaper over time, due to having more time to split the initial cost over.
For the calculation, we need to define how many seconds are you going to use this tractor every month on average. Here is listed as 1800 seconds which is 30 minutes (of real time playing driving the tractor).. That's 6 hours per year. I dunno if that is a lot or not so much. I guess that will depend on the player. I also add at what percentage you can be bothered to repair it. Listed as 80% now, meaning to fit this line, you need to repair every time your tractor has taken 20% damage. The calculation below the 80% number lists that repairing from 100% damage (in 5 20% intervals), will then cost you in total $13.242.
In the table below we list age and total operation time per row. We then calculate:
- The damage taken for this months usage (varies with operation seconds but capped)
- From that we can calculate the monthly maintenance cost. That is, not the cost of repairing it once that month, but the cost of repair assigned to that month, given that you repair it once it is at 80% state defined above. As in the first month you only took 1.86% damage this month, you can here wait for many months before you get to 80% state and repair. At the cap here though, you will get 9.63% damage per month, and you'd have to repair every other month, or about every hour you use it.
- Then we show how many hours between repair you will have at that point, just for additional information. This value dropping low, so you have to repair three times to plow your field, you may think that is a good info point as to when to switch due to depreciation.
- Then we list the total accumulated maintenance cost at that time.
- Then we calculate paint damage taken. We see that even with the average value we added, and the tractor not being used that much, the paint job will be botched already after 17 months, at this time it is way too early to replace if if you want to keep costs down.
- From this we calculate repaint cost. The algorithm for this isn't exact, but the cap is exact, and we reach the cap fast. And before it we have a decent approximation.
- Then we list the price loss due to age, the price loss due to operation time, and approximately the total loss, if we were to sell the tractor at this age.
- From that we can calculate the actual sell price, and the amount of money we lost when selling it (total price - price we got when selling it).
- Finally, we divide on the amount of months, and present the monthly average cost for ownership of that vehicle/equipment given that we sell it at that time.
As it is used a lot more, the cap for operation time is reached faster, so we could actually replace it already after ~20 months without losing out that much.
I can try to add some more examples if people are interested.. I will do some more bits to check how this works out for used gear sold. I suspect used gear is awesome.
Conclusions
- There's a cap to how far maintenance cost scale due to tractors being old. Thus, as long as you can be fuzzed to repair frequently, you don't lose out on keeping a tractor forever.
- However, depending on how much you use it, you can replace it after a reasonable time to avoid having to repair that often.
