I hardly ever sell stuff that's not something I have more than one of. I've done a bit lately, and of course while I was doing general antiques on Ebay I'd sell stuff I had no intention of collecting.
The few collection items I've sold lately were either things that really belonged in another collection, or really didn't fit in mine.
My collection of bikes is pretty wide ranging, but it's mostly team used aerodynamic bikes from roughly 1983-2000. I picked up a very nice tandem a few years ago, rode it once and found out my wife and I just couldn't ride a tandem. I sold it recently to a cyclist I know who is really into tandems, and regularly rides them with his wife. He's happy to have it, and really likes it. I'm glad about that, and my wife is happy that it's not blocking up the back hallway anymore. (Me too, just don't tell her
)
Over the years I've taken short breaks of sorts from collecting different things. Since I usually go for inexpensive stuff I don't really worry about selling. Maybe if I'd spent more I'd be more inclined to sell it in favor of other stuff.
Even Museums occasionally go through their holdings and sell or trade items that don't fit their collections, or aren't likely to fit into any future displays.
I think the storing stuff for a while might be good. You'll probably find that in a couple months there's a few pieces you miss seeing displayed. Those will be the keepers, after that it's just figuring out what the focus will be if any.
Steve B