I often see people say they go to the gym 2 or 3 times a week, and others tell them to go more. But as far as I know, most muscles need 24-48 hours of rest and recovery after a workout, so it's not ideal to work each muscle group out more than 2-3 times a week. Is there a big difference between doing a full-body workout twice a week versus splitting it into 2 half-body workouts so you go 4 days a week? It seems like there shouldn't be, but I'm not sure if I'm missing something.