how often should my baby be pooping? how often does yours?

My baby is formula fed for the last few months and eats solids too but he still likes his bottle better. He seems to only poop once every 2 or 3 days. I looked it up and it was saying it could be because he's constipated from dehydration, but his poops are not solid and he drinks water often while playing. How often does your baby poop?