Truly good tenants wont be in the position to move in "right away"..... but most will jump on a good unit and have some overlap between old and new..... they just have to pay for the overlap... also gives them time to move everything from one to the other, clean up etc etc. 

the tenant that's leaving paid until june 1 and moved out already. still has the keys and checks on the property regularly. new tenant is moving in on 5/21. there is a 9 day overlap where i am double dipping. i asked the current tenant for the keys and she said "will give it back on the 31st". i can easily change the locks/keys, but dont want it to become a big deal.

I am resistant to the idea of paying for the rest of July because (1) She didn't mention this until we moved in (2) She never mentioned prorating our rent for our benefit when we were going to move in after July 1st (3) This is all initially her fault for overlapping leases. 

If they're set in their numbers, and you're set in yours and there's no overlap, don't waste any more time - just move on.

I can see when you have a lot of properties, with a few overlapping, this becomes tough.

Thank you for compiling such a comprehensive list Brian.My own choices have substantial overlap with yours.

Outside of matters like collecting rent or lease violations, I try to think of the tenants as roommates in my head, and when they think of me as a landlord in their head, we end up having this "respect overlap" where we are always showing each other more respect than the other one may feel entitled to. 

If no one likes you enough to go with you can schedule overlapping viewings.

@Steve Vaughan, It's probably not surprising that many of the names overlap - so there is at least some method behind the madness.

If you go the single family route, it could still be profitable on Airbnb because you could rent out rooms individually or as an apartment but you would need to be sure the bookies weren't overlapping.