We have inspections with pictures done, cost $75, every 4-6 months. 

At this point she has said she want to remain in the unit because she is happy there and she likes me as a landlord, but she will start documenting everything and taking pictures.

When I lease properties out now, I take tons of pictures so the move in condition can be shown and helps protects both parties.

If it's clearly junk, I take pictures of it as evidence, then dispose of it at the landfill or at least at another location where the Tenants can't see it.

Having great software allows you to focus more on the bigger picture by giving you built in procedures for common tasks.4) Make sure you have working keys for all your units and that all locks for a unit use the same key, then figure out a key management system.

I like to review the whole picture, example not a strong credit score, I then review the history on the report and can see what chess playing financial moves they had to do, (school system does not train us to master budgets, credit cards, etc, it is learned in the school of life) reviewing the history report you can see which bill account they made priority and which ones they didn't, and if they decided to not pay or skip few payments on non-essential accounts, that's okay with me.

Everyone posts pictures of their new car, of their new home, their perfect family or adventurous vacation.

Take pictures to document how he left the place, change the locks, and move on.

I have had investors get pictures and advertise, show and fill before closing but this can get hairy if there are late problems in escrow like clouded title, not appraising, etc.

Talk to a qualified CPA or EA and let them know your whole picture (way too many variables come into play here) to make sure you are declaring your interest legally and in the most beneficial manner.