You will never regret getting 4WD. For those times that come up when you need it, its a blessing to have. I look at 4WD like buying insurance against a hassle at a very inopportune time.
I used to have a single cab dually about 15 years ago, and drove down the hill to my old hay barn to get a load of squares for the horses. The pasture grass was about knee deep and there was a very heavy dew that morning. After tossing them bales on the back, I hopped in the truck and the truck just sat there and all 4 tires in back spun. I couldnt believe I was 'stuck' on wet grass. The ground underneath was hard as concrete even. Ugh. Same thing with running out to in the pasture to check livestock after a 1/4" rain, this blackland gets slick as grease, but if you have the front wheels pulling you can tractor through those situations easily and never even spin much and cut up the pasture. I would imagine folks living in areas where it snows would certainly benefit all winter also. For what I do with a pickup, I will never go with 4WD again.