I've had several caps on my pickups over the years. I found them to be very handy to have along with a boot for the rear window of the truck allowing a passage way into the cap/bed.
I built a sleeping shelf across the front of the cap that provided not only a sleeping area for me but a spot for our two dogs to lay down during trips. They would look out through the boot and we had easy access to them.
In addition I built cabinets along the pickup bed sides with tilt up lids. This gave me a place to carry stuff and not have it rattle or slide around. So between the front bed and the two side cabinets it made for a U shaped sleeping area with floor space for other stuff. Two of us and the dogs could sleep comfortably for quick overnight trips away from the TT.
All of my caps were wood and siding construction so it required two strong men or three weaklings to get them off the truck. Basically you undo the bolts or clamps holding the cap to the bed rails of the truck. Then lift up the cap and walk it back and set it down on blocks once you've cleared the bed of the truck.
For fiberglass caps you can suspend them from the rafters of the garage using a block and pulley setup. One person operation.
Takes no more than 30 minutes to take of or put back on.