20-25 years is at the limit of what I could imagine staying in one house with any certainty. How does the extra longevity justify the cost unless I plan to never ever move again?
You'll no doubt recoup some of your value, but not all of it.
Witness dozens of TV shows, "You guys had $50K for your reno budget. Your original value was $250K, and you spent $50K and now your house is worth $350K!"