We had to lift the front wheels off the ground (about 4") for the first time to level our RV last weekend.
Afterwords, I remembered people cautioning that air-bags were not designed to support the weight of the front suspension, so I took a look and the bags were STRETCHED! So we immediately adjusted the jacks and repositioned some 2x12 boards under the front tires to take the weight off the suspension.
the people next to us had to do the same, but their bottom RV step was at about 24" off the ground! their RV looked like a 30 footer. They used a little step stool to make-up the distance.
Looking around the campground, most had supports under their fronts, but several just let the tires hang. Wouldn't be a tire problem with no bags, but some were DP's and I thought all DPs had bags.