I had 20+ mile commutes for about 16 years and never once worried too much about the impact of those miles on the value of the car. I purchased the cars so I could get around and enjoy my time in the car as much as possible.
Commutes were (one way):
- Atlanta: ~28 miles. Fortunately only had this for about 6-8 months since it was in traffic hell (~30 min without traffic, but could be 2+ hours if I left at the wrong time...)
Phoenix: ~28 miles for 9 years, then ~23-24 miles depending on route for 4 years after our office moved. Both of these were mostly against traffic, so weren't too bad -- roughly 30 min (the closer office had less freeway...)
Cinci: ~22 to ~29 miles depending on route. I usually took the shortest route in and longest route home to minimize traffic -- both of those were mostly freeway and ~30ish min. But there were non-freeway routes that I sometimes needed when there were accidents -- and it could take up to an hour each way. About 2x per month it took 45 min due to an accident and an hour every 3 months or so...
But now that I'm in TX, my commute is just a few feet