mkirsch, My camper originally had 3 wing mounted jacks but when I got it 2 of the 3 had rotted off. During the rebuild I switch to 4 corner jacks but hind sight being 20/20 I realize I didn't sufficiently beef up the corners enough to safety use the corner jacks. Now that the interior is back together I was hesitant to undertake the proper corner improvements to keep using the corner jacks. Just too much to take back apart for access. I also never liked when I used the 4 jacks how one was always unseated. Switching back to 3 jacks was an easier choice as all the work was on the outside and was pretty easy. If I had the money I would love a Stable-lift but they are just way too expensive.