@Melanie802
Already great suggestions from @Shelley159 & @Helen3 .
We also send a message the morning of check-out around 8-9am thanking them for their stay and remind them checkout time is XXAM and our cleaners will arrive shortly after to prepare for incoming guests. We also ask them kindly send us a message when they have checked out (even though we can see them leave on the cameras). Then state since our cleaners have limited time to prepare for incoming guests, we do charge a late check out fee. Be sure to add the late check-out fee to your addl House Rules. Not departing at checkout time is a violation of standard House Rules on your listing according to Airbnb.
Violation of House Rules
https://www.airbnb.com/resources/hosting-homes/a/how-to-dispute-retaliatory-reviews-552
"...You should feel comfortable hosting guests without worrying about the possibility of receiving a retaliatory review. You can dispute a retaliatory review—no matter when it was posted—from guests who commit a serious violation of policies, such as:
Damaging your property
Overstaying their reservation
Violating your standard house rules
Having an unauthorized party or event at your place..."
If you have a smart lock, be sure set it so their code will expire around 10-15mins after checkout time.