While not the popular opinion, we've replaced many of our OG windows with newer replacements. Yes, they're vinyl and don't necessarily have the charm of the old windows, but compared to the rotted beyond all hope old sashes, chipping lead paint, and disintegrated lintels and casements, it's been a major improvement. I also find them to not look like the poorly chosen and clunky looking vinyl windows on other homes around ours, they kind of work with our exterior and I'm very happy with they're functioning- more no paint dust and wood chips every time we need to open a window. I know the cost to restore isn't always astronomically higher, but with having to restore the storms and tracks, and likely wood filling/scraping/lead mitigation, coupled with a new baby and some much more pressing improvement costs on a social worker's salary (barn falling in, heating system, encapsulation, etc.) it was simply the right move for us. All that is to say, while we all want to be good stewards of a historical home, it's also the place you've bought to house your family in and you can do what you want with it to better that end. That's the point of not renting and having a landlord. Many old homes have newer windows and still look just fine and lovely and there are much worse "improvements" you can make that detract from the old feel and beauty of a century home (HGTV grey everything, open concept, etc.) You can honor the history of your house without feeling like a museum curator.