My pup is getting a free run across fields in morning, probs 20 mins total, just wandering and throwing a ball etc to try and master the retrieve and recall.
Then about 20 mins road walk at night, sometimes 30 mins depending. He is 4 months next week.
Most Sundays I go out with my mate for a mooch and pup comes along, that's anything upwards of an hour. When he was really young I carried him after half hour but now he does the whole walk and still runs around at home.
Gaz