Hermit crabs live on a constant house-upgrading. They need to move into a new larger shell as their body grows bigger. In case an M-size crab finds an XL-size seashell, he does not discard it for being oversized. He waits next to it until an intermediary L-sized specimen arrives and abandons his shelter, passing it on to the M-size one. Although this social network and synchronous vacancy chain behaviour may require hours of queuing up, the gathering helps everyone to inherit a suitable house in the end.
We, as humans, also suffer from this real-estate fever, always looking for a higher quality static dwelling.
But the ones who choose a nomad lifestyle prefer simply to keep the same shelter while ameliorating only the surroundings; thanks to Recreational Vehicles, a minimal shell-shelter can be attached to a pedaling device, and moved on to an upgraded site: scouting new XL-size locations while keeping one’s XS-sized home.