Say you need a big 4 wheel drive car to get the family to alta. Most days you cant get up the canyon with 2-wheel drive. Also you should bring a shovel to get your kids out of the snow when they fall on deep days. The family needs to bring a lunch because it's so expensive at the mountain.
In response to the Duct tape hippies comment. Duct tape is essential to the ski bum. If you ski hard in the trees, dropping cliffs, your gear is bound to rip. They do have duct tape in almost every color now, so you can make it look pretty cool.