We had replaced the carpet in our nanny’s room with tile in that room.

The work involved scrapping doors, window sills and replacing 11 old porch windows with new Diamond vinyl windows.

I replaced the HVAC in 2012, water heater in 2010.

I just signed a lease in an apartment and my year 1 goal is to replace my monthly rent with cash flow from investment properties.

Tenants were 1-2 months from lease expiration, so was able to replace tenants at, or above, the prior rents.

Over the years we have replaced/repaired every system you can find in a SFR except having to pour a new foundation. 

Should I replace the back door lock even though she doesn't use the back door and it still locks from the inside?

My area it is $6 sf to replace floors with a medium price lvp. $7200/10/12 months in a year=$60 per month.

I find financing, look at wholesale deals of single family, run the math, if cost+rehab+holding+insurance is under 60% ARV I write scope of work, get financing and insurance and buy, get bids from contractors I've vetted, write good contracts with a real estate attorney, hold contractors accountable daily or replace them, get second opinions along the way, pay contractors as work is done right, sell the thing at a competitive rate, pay off financiers and profit.

Good option, cheaper than replacing flooring and ceiling drywall beneath.