What is the legal number of days for a tenant to give a landlord for non-renewal of a lease?

According to Texas state law,  the obligation to refund a security deposit shall occur on or before the 30th day after the date the tenant surrenders the premises.   A requirement that a tenant give advance notice of surrender as a condition for refunding the security deposit is effective only if the requirement is underlined or is printed in conspicuous bold print in the lease itself. I have not located either 30 or a 60 day requirement, but the lease itself may give a timeframe. The lease usually ends at the end of the lease term as set out in the lease itself.  If you do not intend to stay or renew, you should give notice based on the method set out in the lease.  If none is given, usually reasonable notice is the rule of thumb and it would be better in writing.  Most lease terms across the country usually use a 30 day timeframe for notice, some states do require 60.