Carpet, cabinets, tile, lights, etc. 

It's far from an "official" metric but if it costs $200 to get a unit rent ready (touch up paint, locks changed, carpet cleaning, etc.) and your rent is $300 that's a pretty darn high percentage.  

You can close on it this month, spend some money cleaning it, advertise it for rentals, all the money spent will be ordinary expenses, and be on the schedule E.You'll have to capitalize if your do something like carpeting, I give it a five year life. 

If you own it yourself you get to (or HAVE to) make the repair vs. replace decisions, decide what to buy, when to buy, when to sell, if you want to pay more for tile floors or put in the cheapest carpet, etc.  

I mean, surely some repairs (paint, carpet, roof) vary with the square footage of the home but appliances and many other things definitely don't care what size the house is. 

Several times, we have purchased a primary owner occupied house, improved the house with paint and landscaping, carpet and occasionally an updated kitchen or flooring.  

I don't do carpet 99% of the time,doesn't last.

To do this I bought homes that needed new carpet, paint, and health and safety items.

The tenants seems to be late every month and the property will for sure need repairs on carpet and paint once vacant.

If they want new floors/carpet or major issues, you should tell the they rented the place as it is.