I then retain their keys with a tag on it for a period of time in case there is ever a question if I changed the locks.

I have recently stumbled upon this website to learn and retain a lot of the information provided.

Seller retains the tax shelter (expenses, interest write-offs).Lease purchasing (lease-to-own) puts pre-qualified, reliable tenant/buyers in now-vacant properties.

Note that this is not appreciation, it is just your hard asset retaining it's value while the money is only worth half of what it used to be.Say you then did a tax and cost free exchange of a carbon copy house across the street.

I feel that I retained more from the class than if I would have taken the class online.

People will always need shelter.So your real estate holdings will always have a value and they will retain that value.

Would you pay a renewal fee for every time they renew and retain tenants?

Their furniture and clothing will trap the odors from smoking too, so as long as they live there the place will retain the foul odor.

The previous owner did a bunch of work to correct these things, however when the code inspector came out he noticed a few small things such as painting, some wood rot, and a retaining wall that needs to be fixed.

If  you have to pay a retainer to subcontractors, materials or incur other expenses then that should also be stated in your contract and not be a refundable amount if you, for good reason, stop work, like not being paid.