How often should I exercise?

Good question. Here's what I tell my clients.
For weight/strength training, every other day is great, or 3 days a week, just never do two days in a row for the same muscle(s). There needs to be a recovery day in between; this is a must.
Cardio can be done every day, but I always suggest one day off a week for letting the body really rest and recover.
That day off never seems to be a problem for anyone.