These tenants aren't careful about their cats, either, so the carpet develops a rank odor. Luckily the Blue renters don't stay long, but they leave quite a mess. That attracts some scary tenants who fight with the next-door neighbors, and the police are called. After this happens a few times, other neighbors decide they've had enough. After 10 years, the Green house block looks pretty much the same - nothing fancy, just a block you wouldn't mind living on.
Renters come and go, the owner fixes what needs fixing and keeps the trim painted.
Her tax appraisals show a gradual increase in property value. Appraisals on the Blue house stay flat. Several adjacent properties have followed the Blue house pattern and gone to seed. Landlords find they can no longer get the same rent as before, so they're forced to lower the rent. With less rent coming in, they don't want to spend as much on maintenance.