How you avoid a tenant from claiming to a court that you didn't address damage deposit funds on time OR a tenant contacting you months after getting out of your property wanting a deposit back and again thinking they might take you to court is to do the final disposition of their deposit funds with in the time lines your states laws allow and sending it thru the mail to the last known address , the one they rented from you , If you use regular mail then do it at the very least with a certificate of mailing. IF the tenant did not put in a forwarding address that letter will still be left there by the carrier, IF you send via certified mail and post office notices are ignored by tenant OR plainly not picked up Post office will return it to you, keep it sealed in original envelope as if you would need it for court one day. If a tenant walked out on a lease some courts will still want you to use the date they moved out / date unit was returned to you AS the starting date of the time line to get deposit disposition done. You wrote >• The old lease will be dissolved once a new lease has been signed.< that doesn't matter when it comes to deposit disposition laws but it would matter say if it took you 3 weeks to get a new tenant and wanted former tenant to pay for the three weeks of rent they didn't pay for. You wrote >• Start date of a new lease is required to complete the new lease.< has nothing to do with deposit dispositions BUT I cant imagine how a landlord could enforce a lease when it didn't have a start date. You wrote >>• If the prospective new tenant flakes out and does not sign for any reason, the current tenant now has a new legal move-out date that could be months shy of the original lease termination date. << This has nothing to do with deposit dispositions BUT would impact a final court claim from a landlord who wants to sue a former tenant who broke a lease early and left owing rent EG tenant under lease moved out with 4 months left to go on that lease, it took you 2 weeks to find a replacement every thing is all set to go , new tenant passed screening, was ready to sign a lease with you and wigs out and refuses to sign& pay , start all over , and this time after you get in touch with the one that would have been your second choice or you start all over and do find another customer and this one pays you and signs at same time but it took you another ten days then it would be fair of you to claim 24 days of rent is owed from the tenant who broke their lease.