I've turned my property over twice (meaning I'm on my 3rd tenant). First tenant did about $5,000 in damage after being in the house for two years. She had a bunch of pets she wasn't supposed to have, and the whole place had to be re-carpeted and repainted. She was also a bit of a hoarder, and it took a bit to clean out the place. It sat vacant for two months, which cost another $2500 in lost rent. So, that averages out to about $3800 a year in just that, plus there were some smaller repairs in between.
The tenant after that skipped out on paying a month's rent and getting it ready for the next tenant cost me $2500 out of pocket (including court costs for eviction. This is after I kept the security deposit). Then, it was vacant for a month. That's about $5000, and they were there for 16 months, so that's about another about $3800 a year.
So for my single family home, it's pretty consistently $3800 a year not counting smaller repairs and not counting any big CapEX expenditures.
The thought that you're only going to spend $2500 per year per unit is just pure fantasy.