I had a bit of a windfall just after we had paid off the mortgage about 15 years ago.
I had better insulated the basement and attic and put a higher effiency furnace while paying the house off.
Unmarried uncle on my moms side, who I did not know that well passed.
But he had a few heirs via his siblings kids that saw some of his estate, along with most to a bunch of good charities.
With the sorta found $30K , and some of our own saved funds we accelerated execution of the next planned project.
We replaced all the windows and doors with 50 year newer ones that were way less heat and noise leaky.
And peeled off the faded siding and too small gutters.
Put 2" foil faced rigid foam board wrap over the second storey, then new second story siding and larger roof drainage system.
This made it the house to stay in for us.
Cut running costs, and made the bedrooms so much quieter.
We live on a minor collector road with a 7 day bus route on it.
I no longer start to wake up when the 5:06am first bus of the day goes past.