Yeah - there's a line somewhere when it is the best time to trade in. Years ago I heard it was 2 years or 10 years. But nowadays with so much 0% financing it makes a difference - you loose only depreciation value but not both that and finance charges which are the most at the beginning of a loan.Depends on how you look at it. I ran my 99 dodge until it was worth nothing. Had to come up with 42k to get the 16 F250. It came with a 3 year warranty . I don't put a lot of miles on it so when the warranty is up I will likely get a new truck. part of the deal was free oil changes. So when I trade in I will not have spent anything on maintenance. The cost to repair the new tucks is outrageous and I don't trust all the electronic stuff that's on them.
I've been in the 10 year club for some time. I am at almost 9 years now and not getting nickeled and dimed....yet. A couple $400 repairs the past couple years but that was it. What was killer for me was paying 5.9% interest back in 2009 on a 7 year loan. Went all out with that truck and will never do it again - at least the long loan. I thought I would never pay it off.
Leasing, while probably not the best financial way to do things, is now a popular choice for me. I've never leased a vehicle before but if I do get something new the next few years it will be a lease. One big advantage in my eyes is just what you said - with a 3 year lease it will be under warranty the entire time.