"Your old windows have lasted since your house or building was built.
They could last that long again with proper maintence".
Contrary to the popular belief that all old windows should be replaced by "modern" ones, there are many reasons to think twice before doing so.
Windows should not be replaced unless absolutely necessary.
Wood windows are energy efficient. And in conjunction with a standard exterior storm window unit, provide a better energy standard than double glazed [thermo-pane] windows. Older wood windows do not necessarily have higher maintence costs. For example, replacing the glass in many of the newer windows requires removing and replacing the entire sash, or even throwing it away and ordering a new one.