AirBnB does not collect security deposits, so I setup OwnerRez to collect the security deposit as they recommend in their documentation (https://www.ownerrez.com/support/articles/security-deposit-h...).

We had a tenant move in 4 years ago and pay their security deposit.

If you can't do that just give the whole deposit back it is less risky. 

where is the best place to keep the tenants deposit?

First month’s rent, last month’s rent, deposit, pet fees, admin fees, utility setup.

Deposits are not meant to cover routine turnover costs.

Long story short new tenant had a reversal on their first months rent and security deposit.

Let them know they may lose their deposit if PM does not turn them over at some point.

Get the locks rekeyed and get a deposit next time and make sure your lease includes verbiage about keys, when they will be returned and what happens if they are not. 

chaos to near-zero.If you use a PM, you still want your own clean accounts + PM statements.2) Weekly 10-minute routine (or every other week if you’re small)Scan new transactions.Categorize anything unclear while it’s still fresh.Upload/attach any receipts you don’t want to lose.3) Monthly 30-minute closeReconcile bank statements.Confirm rent deposits match leases / PM statements.Review the “uncategorized” bucket until it’s zero.Tag anything that’s CapEx vs. repair (this matters a lot at tax time).4) Use a rental-specific chart of accountsYou don’t need something fancy — you just need consistency.