@Nick L. as @Nathan G. stated, getting too many bids can strain relationships with contractors that do a good job for a fair price.If an owner insists on multiple bids, we will get one from a trusted source and then two from random contractors.

They'll tell you that wooden sash windows can be repaired to be just as good as new vinyl windows with argon-filled cavities between window panes and well-insulated weight cavities.

You should have newer windows if you want your house to match the best comps in the neighborhood.The difference between the super good windows and any new windows (double pane) isn't really there.

Plenty of people will gladly pay a premium to live in a restored old house, and vinyl windows aren't usually part of that.Here's some reading material: https://www.amazon.com/Save-Americas-Windows-historic-windows/dp/146628644Xhttps://www.amazon.com/Window-Sash-Bible-Maintaining-Restoring/dp/1505299144I'd rather spend $250/opening replacing cords, fixing broken panes, installing weather stripping, and installing/tightening storms (all of which will give you the same efficiency as replacements) than put in vinyl.I say all this as a guy who eventually caved and put in 45 vinyl replacements in my own residence.

They make replacement windows onsite, in the $200 - $250 price range for single-hung, vinyl double-pane, energy efficient windows.  

The relationship is strained. 

The other option was an off market property in Vallejo, but as new landlord I wasn't ready to manage something like that and the costs would of put more strain on me to operate.But you your point, had I done that I would of made some crazy appreciation.... 

COVID has a put a strain on everyone so I don't want to beat them up to badly.

All windows are single pane. 

What I don't suggest is taking a friend or family member's money that could strain a relationship down the road.