If you're paying $20k every 20 years, that averages out to a $80/month "window subscription" when itemized
That said, my property is really old and has effectively all window types in one place or another. Because it had 15years of lack of maintenance I can see which are repairable, which aren't, and how fast each degraded.
The really old windows aren't much of an issue (as OP said). Reglaze, reseal, performance is decent.
Cheap wooden windows are more of a problem, but repairable and upgradeable.
Cheap plastic windows have not fared well all. The plastic frame isn't in place due to heat/cold/UV exposure and they're a full replacement. They leak tremendous air and let bugs in.
The aluminium windows have fared a lot better.
That said, my property is really old and has effectively all window types in one place or another. Because it had 15years of lack of maintenance I can see which are repairable, which aren't, and how fast each degraded.
The really old windows aren't much of an issue (as OP said). Reglaze, reseal, performance is decent.
Cheap wooden windows are more of a problem, but repairable and upgradeable.
Cheap plastic windows have not fared well all. The plastic frame isn't in place due to heat/cold/UV exposure and they're a full replacement. They leak tremendous air and let bugs in.
The aluminium windows have fared a lot better.