Question regarding 30 day notice...

[Pat Martin]

I have a tenant whose lease is up August 5th and she contacted me today saying they will be leaving at the end of lease.  Im guessing that she does not have to give 30 day notice because she's just following the lease, but how do you guys deal with that so that you don't have a tenant tell you a few days before end of lease that they will be leaving?  She verbally agreed to resign at the end of the term but then changed her mind.  Also how early would you have them sign a new lease?  A month before end?  Thanks!