回复：租客要提前5个月退出一年的租房合同

All my leases have an intial term of 1 year, then become month by month afterwards. If I were you, I would ask their cooperation when your propective tenants come to see the house. But I would not penalize them for terminating the lease now because they are buying their own home. Instead, I would send them a note to congratulate them and thank them for being a good tenant in the last 7+ years.