I've owned 2 different 4x4 dually's in the last 10 years, and only very rarely used 4x4. A few years go the snow covered Indiana pretty deep and I used it once going and coming from work (I live in the country and drive 22 miles one way to work).
This is the first year I've REALLY used 4x4 and since about January 3, have used it almost every day. We got hit with horrible snow, and the roads were awful. So, once I could break free of the drive way, 4x4 was my best friend. Last couple days the snow melted, and today we got hit with another 2 inches or so. We (my wife and I) took the truck to work this morning driving 2x2, but when that snow started today and the drive home the roads were a horrible mix of wet, snow packed, slush, ice, plowed, and not even touched, I dropped it back into 4x4, and "she" just purred right along!
You may never use 4x4 for years, but the 1 time you need it, you'll be SO GLAD you have it, all the money in the world won't make any difference!
Edit:
I just remembered, several years ago we left Indiana to go to Norfolk, VA. My daughter was "suppose" to get married that week. We scheduled a campsite at First Landing State Park. The morning we were scheduled to leave, we got hit with a blizzard in Indiana. We left anyway, and it followed us all the way through Indiana, Kentucky, and Tennessee, North Carolina, and did not go away until we crossed over the mountains in Virginia. The entire drive was 2 days, white knuckle driving through those snowy mountain interstate roads, and I drove 4x4 all the way. We had to stop and stayed in a motel somewhere in Tennessee. Oh yea, 4x4 ... you bet! Sooooo glad I had it!
This is what we looked like once we crossed over the mountains!