The short answer: if you make no claim against the deposit, you must return it within 15 days of the tenant moving out. If you intend to keep part or all of it, you must send written notice of your claim — by certified mail — within 30 days, and the tenant then has 15 days to object.
Holding the deposit
Florida requires you to hold a deposit in one of the prescribed ways — for example, a separate account (interest-bearing or not) or a surety bond — and to disclose how you are holding it. Commingling a deposit with your own money is where many small landlords go wrong.
Returning it — the timeline that matters
No claim: return within 15 days. A claim: written notice by certified mail within 30 days, stating the reason and amount; the tenant has 15 days to dispute in writing. Blow the 30-day notice and you generally lose the right to impose the claim at all.
A newer option
Florida law also allows landlords to offer a recurring monthly fee in lieu of a traditional deposit. It is optional and has its own disclosure rules — useful to know exists, worth getting right before you offer it.
This is the kind of deadline that is easy to miss and expensive to get wrong — one more thing management tracks for you.
This is general information, not legal advice. Florida statutes change and every situation is different — confirm the current law or speak with an attorney before you act.