There is no incentive for them to find you good tenants or to do repairs in a fashion that saves you money - because they usually profit whenever there are repairs, or finding tenants, or kicking out tenants, etc., etc.  

Savvy tenants aren't going to just believe you when you say it will be cleaned and painted and in pristine condition and available on the day it's supposed to be - when they are stepping over someone dirty laundry.And, they won't feel comfortable looking inside closets or the garage, etc.And, there's the potential liability of your current tenant claiming some expensive jewelry disappeared during your walk-throughs.I know the idea of having to eat a month's rent in-between tenants hurts, but I truly believe you get better tenants, who will not be as likely to cost you in problems, if you clear out the last one, get the unit in beautiful show condition, then start showing it.  

No vacation plans/photos, new car, expensive jewelry discussions ever again. 

If you don’t approach this in a business like fashion you will be the one that suffers.

As soon as stainless steel came into fashion I thought they were already outdated things that are going to be dated any day now. 

So, even though I got them to move out in an amiable fashion, I think they could sense that if they didn't, I'd be happy to nail them to the wall LOL.  

Just to add....the security deposit isn't identified as his or hers, so for you to split in any fashion, even if you wanted to, is a recipe for you to be taken into court by one, the other or both. 

They never get back timely fashion, so send a few reminders.

When was the last time you ever had a window break itself in that fashion in your home? 

If debt could be used in a similar fashion in the stock market then the stock market would clearly be better, but you can't.