It's always advisable to train the dogs everyday. And contrary to what others say, most trainers would recommend starting the first day you get your puppy (but certainly not when it's still a new born).
Do you train your pups? How long is one training session?
At what age did you start?
How often do you do it in a week?
What are the rewards your dog respond with in training? Does he settle for belly rubs, back strokes, treats or kisses?
I would admit that I'm a bit lazy. I don't do so everyday but when we do, we often for 5 minutes twice a day and they're highly responsive for treats.
I trained when my dog was a pup still probably 2 weeks - 3 years old. One training was about a half hour every day to every other day. The reward was treats. She now knows a lot of tricks