I'm sorry that has been your experience with your tenants. But it has been my experience that tenants who are checking these things (window etc.) make the best tenants. Anyway why would a landlord let his property fall into disrepair as such. As the weather improves, tenants are opening windows, which should open properly. Perhaps as the days are brighter, the landlords poor repairs are now becoming obvious. If the landlord had properly kept the property up, this problem would not occur.