yes i agree with what your saying, but if they as a young couple , say with 2 kids, a 3 bedroomed house,after say 18 to 20 yrs, the kids leave home, there are 2 empty bedrooms, if its in the tennancy agreement they know fine well whats to come right from day 1,and be prepared knowing whats to come, im not saying its wrong or right, but anyone who in the same way have a lease, they know it will have an end date