This is essentially true... and was the primary culprit of the DEF system I had to replace in my dodge. The dealership after they fixed it told me to run it as a cycle, not fill it every chance I get (basically don't keep it full) and the absolute worst DEF I could use was the stuff at gas stations in underground tanks right next to the pump. I didn't realize it when I first started buying DEF diesels but the life of DEF is about 45 days, and that clock starts ticking from the time it goes into that underground tank. It's better to go into the store and buy the sealed jug of it. Unfortunately for me it's rare to burn an entire tank of DEF in 45 days... I don't think I ever have. Infact a DEF tank typically lasts me about 1 1/2 oil changes and I'm not very often putting on enough miles to be adding new DEF every 45 days. I'm not a mechanic or gear head so I generally heed to the advice of people that know a lot more than me (which is usually most people
). Most, if not all, of my DEF diesels now have a heating element to keep the def from freezing while in operation. The only reason I know that is because I've had to replace 3 or 4 of them along with the sensor that reads the DEF temps
.... To my knowledge they can still freeze while they aren't running.
One other concern I'd have with owning a diesel purely for recreational purposes is down time for repairs. If you can afford the additional time to repair a diesel then disregard this. But warranty or not.... they take longer to fix. I've had a diesel in the shop for 5 weeks for just one fix, never had that with a gasser. Most of the time when one of my diesels go down it's 1-2weeks out of commission. If that's what you're relying on for a September elk hunt, it's worth considering. I think the longest down time on my gassers in the last 5-10 years is 4 days... I have a pair of 2015 Dmax's right now that in their first year were out for roughly 2 weeks each. That's a full month I was without a truck that wasn't "paying for itself". It was all warranty/recall work but a pain nonetheless and GM won't reimburse lost income.
Lastly I don't doubt or dispute other's claims on here about having to repair gassers., diesels in theory are more economical, etc... I'm quite possibly the least fortunate human being when it comes to vehicle repairs but my gassers to diesel ratio is pennys to dollars between the two. Diesels are a neccessary evil for me, and for other varities of contractors... it's why concrete is what it is per yard, trees cost what they do to cut, houses to build, etc... Obviously there's other things driving costs also but equipment maint. and repairs is a slice of that pie.