As always, it depends. In the Northwest, there is generally very little rust. I look for one or two owner vehicles from the Northwest without wrecks reported by looking at Carfax and Autochek. There is no guarantee, but I can afford to buy used and gamble that I can do a lot of work for 30k or more that I save.
I used to always buy new. Like others here, I've traded perfectly good vehicles in the past that I bought new just because my needs changed. Essentially, you are looking for one of our tradeins.
Modern engines of gasoline or diesel should last hundreds of thousands of miles. Buy what has enough power. I bought diesel last time to have enough power for a large fifth wheel in the future. I'm sure I could get by with gasoline to just haul my tc.
'10 Ford F-450, 6.4, 4.30, 4x4, 14,500 GVWR, '06 Host Rainer 950 DS, Torklift Talon tiedowns, Glow Steps, and Fastguns. Bilstein 4600s, Firestone Bags, Toyo M655 Gs, Curt front hitch, Energy Suspension bump stops.
NRA Life Member, CCA Life Member