Depreciation is a curve, essentially you lose the most absolute value within the first 3 years, the curve then starts to flatten. a decent rule of thumb is 12%-15% depreciation yearly.
Maintenance is typically the inverse, items wear faster over time, so the first 3-4 years are the most reliable, at year 4-5 you’ll see more maintenance due (same at year 7-8). Maintenance as a % of vehicle price can usually be calculated as 1% the first year doubling every year. For example year 1 on a 60000 vehicle might run $600, where year 4 the same vehicle might be worth 36k but you might expect to spend more like 3k in maintenance.
These are all estimates. Actual values vary, but decent for budgeting.