HCA: Hermit Crab Association

Should I start looking for some new shells for my large crab? I've noticed that he spent an hour inspecting a shell last night then finally watched him get in it. After he got in he took about 30 seconds to run over and get right back in his old shell and got right back in. He then starting looking at others but didn't seem satisfied. Is he not happy with his shell lol? He obviously doesn't like his selection available...
My guy that came up from a molt (first successful :]) also been kinda shell swapping happy too. He is smaller though around medium and been switching and going back to his old shell as well. Same behavior pretty much except he has a bigger selection than my large since I have a few his size.
It has been interesting to watch them swap though lol. They look weird at the bottom.

Try boiling all of your shells in salt water, then letting them cool and put them back in. That can help sometimes.

It wouldn't hurt to give him some bigger shells. My pp Kathulu would change shells every couple days always going back to his original shell. I finally got some bigger shells and he switched into one of those and hasn't changed back and has been in there for a two weeks with no changes

I think it's normal, I catch my crabs trying on other shells all the time, they also switch shells more often then it seems people mentions theirs do. Maybe it's because I have so many and I wash them and replace them every 3-5 weeks. But they all seem happy, I have no shell fights, and everyone is in nice size and looking shells.

I'll try the boiling water to see what happens. I also found a huge lot of shells on ebay with like 100 shells I might order just to have extra shells for them. I can only recognize like 2 of my crabs now since they swap so much. The big one and the molted one. Other then that they all just confuse me haha.