Windows show very clearly when neglected. “Squeaking and creaking noises when opening and closing are a red flag,” says Frank Lange. “This also applies if the windows can only be locked with some effort.” The easier it is to open and close the windows, the less wear there is.
A little care protects against this. “Every two years at the latest, the inside of the frame should be cleaned and the moving parts greased,” says Lange. Thomas Gerke recommends sewing machine oil to keep the mechanical parts in the window crease in good condition.
Joints also last longer if they are creamed regularly. Gerke recommends care products for car doors. Alternatively, a special glass maintenance milk prevents the seals from hardening and losing their effectiveness.