We have a 1960s home with single paned aluminum windows from the 90’s. The window frames themselves look okay but the exterior siding wrap and casings appear to need to replaced (wood underneath is exposed and rotted) and also we need to re-caulk around windows. We received a quote for the repair, however, I've just noticed condensation and mold growing on window frames inside our home on many of the windows.

My question is should I hold off on exterior window wrap repairs and save up to replace windows first or can each be done separately without being done in a specific order? We have over 20 windows so replacing them all is a big expense for us.