After some thought, I do think I'm going to try selling my 10-22mm. The price I could get for it is too alluring to just sit on it like I have been. If I want to play with an ultrawide, I think I can always rent one.
This thread inspired me to look at the photos I've taken on our last few trips. Some of them, such as regular trips to northern Michigan and Myrtle Beach, were easy, since the 10-22mm stays at home then. However, on our last two summer trips to Yellowstone last year and Niagara Falls / upstate New York the year before, I only had a couple of "keepers" that were taken with this lens. One of the American and Canadian Falls from the top of the Skylon Tower in Niagara ended up getting enlarged as a sudo-panorama shot, but the only one from Yellowstone was nothing special.
My original plan was to keep the 10-22 for my upcoming two-camera system, but I may instead just sell it to help fund that second, full frame body. I seem to be using the lens less and less as the years go by. This summer's trip is to the Smoky Mountains and Blue Ridge Parkway. I never used the 10-22mm on our previous visit there when I had a dSLR.
BTW, here is the shot of the Falls I turned into a panorama. An ultra-wide lens was the only option, as I needed to lean forward and stick the lens out through an angled chain link fence from the top of the Skylon Tower. There was no way to setup a tripod and try to make a multiple exposure stitched panorama, even if I wanted to.