A landlord must wait until six months from the expiration of the current lease before requiring a tenant to renew the lease, if the lease is for a period of time longer than ten months. Nothing prevents a landlord from waiting until closer to the expiration of a lease to ask a tenant to renew the lease. Any provision, whether oral or written, of any lease or other agreement whereby any provision of this section is waived by a tenant is contrary to public policy and void.