Murphy was 13 weeks when I got her and I started walking her almost right away. We walked for 10 - 20 minutes twice a day and worked up to an hour first thing in the morning by the time she was about 6 months old. We just got a little 10 week old bedlington terrier puppy and he's much smaller. I'm walking him once a day and started with just 10 or 15 minutes. I judge by how much energy he has. If he starts to slow down, we call it quits.