When it becomes a hassle or the costs don't outweigh the benefits then it's time to take a hard look at what to do next.
We were in the same situation a few years back; our 2-4 monthly trips were becoming more like a trip every 2-4 months. The kids had grown and were off to college and time wasn't what it once was.
I bought a TT for a project and to use on a hunting trip. After I got home we started thinking, why keep the MH? One trip I had to pull the TT to the campground then drive home and get the MH. I hadn't gone 10 miles when I knew keeping the MH was the right decision - for now. It's paid for and we are trying to adjust our schedules so we can get back to using it like we should.