Hobbies And Interests
Shell Size
A hermit crab only needs to change shells when it has outgrown its current shell. According to Animal Corner, the pace of this is directly affected by the size of the shells as crabs with shells that are too small cannot grow as fast as those with well-fitting shells. Since this affects the rate at which they will transfer, the availability of at least three or more shells if you're keeping a hermit crab as a pet will inspire more frequent moving and growth. Healthy hermit crabs can live between 20 and 30 years.
Shell Cleanliness
Hermit crabs can't clean their homes, so often they will abandon a dirty shell for a cleaner alternative. When a hermit crab is sick or molting, it may also leave its contaminated shell in favor of finding a new one. When keeping hermit crabs as pets, providing shells that have been boiled and dried before being placed into the living space ensures plenty of choices for the fickle crustaceans.
Communal Moving
Putting other hermit crabs in the same tank may inspire multiple instances of switching if at least one empty shell is placed in the tank. One way to facilitate this is by placing a shell in the living space that the largest hermit crab could transfer into. After the crab makes the first move, the next largest crab will take the original shell of the first crab, and the process continues down the line.