Rick uses his magic daily and Rita rarely does. Rick's always had access so it comes to him as naturally as breathing and lets it just happen. The way shifting works involves a shifter mapping their own body to the animal they're turning into. Since Rita had her colostomy young and was collared for most of her youth she didn't have time for it to become muscle memory the way it is for Rick, however once she started really focus on her abilities, she quickly surpassed Rick's skill level. She mostly uses hers while working in the garage and cooking to reinforce her skin and bones and such. Rick mostly uses his to showboat lmao, but is an overachiever who loves to flex how much he knows.