It costs the same to repair a refrigerator, change a lock, clean a carpet, whether the rent is $500/month or $1,500 per month. 4.)

In this case, also be sure to take into account the age of other capex items: how old is that water heater, what's the condition of the flooring, is there carpet that needs to be replaced, floors refinished, how old are appliances etc?

I have had smoke damage and have had wax spilled on the carpet.

There are no carpet or upholstery in the home that were supplied by me.

If I were a betting man, I’d guess that opex would be closer to 50% given a lot of expenses are fixed (lock change, carpet cleaning, owner paid utilities, appliance repair, just to name a few) regardless of a unit renting for $500/month or $800/month.

I have put it under the carpets for now and when I redo bathroom and kitchen floors, I will put it in the traffic areas under new tile floors or maybe engineered wood..not sure yet.  

I do my own hardwood floors but let a pro do the carpet.

How old is the carpet?

Mostly just need to replace drywall and paint, new carpet and some minor bathroom repairs.

Here's what I know of the numbers: House is 4 bed/3 bath, 3100 sq ft$55k is owed to bring everything current (HOA, mortgage, fees)$8-12k for rehab - general cleaning, landscaping, 1500 sq ft of carpet, interior paint in some rooms$164k - current loan balance, $155k after bringing loan current, PITI is currently $1076 @ 3.5%$1800-1900 current rents in the areaIf the loan were called, I would be able to pay it off.