It really does depend on the dog's diet as well as how often your dog eats a day. If your dog is being fed a high quality food then it will normal poop less often. If the dog's being fed a lower quality food then it will probably poop three to four times a day.
Every animal should defecate every day. Generally with dogs, they will need to poop 15-45 minutes after they have eaten. If you suspect a problem, consult your vet ASAP.