Always stick your neck out for the good tenants and replace the bad ones as soon as you can.

This is a separate concept and does not replace the 750-hour requirement for REPS.

Just replace and move on. install lights. 

One can get a known median estimate of replacement cost, and can factor an inflation rate.

If finding a new replacement is more difficult then get your new property under contract first even before your old property closes.  

If they've collapsed, they will need to be dug up and replaced.

Imagine investing in all new, beautiful finishes, only to discover that the drain pipes are faulty and need to be replaced—an issue that could have been identified and addressed beforehand.

Financial independence requires more than just replacing your current income.

However, I wouldn't necessarily recommend full replacements of any or all of them. 

One golden rule I follow,if it takes a long time to fix/replace when it breaks, don't buy a cheap one.Imagine, this thing breaks in the middle of your peak season and the people who can come out to rebuild are 2 weeks out....It takes at least a day or two to build something like this even if you are super skilled.