Well, Rosey got more exercise when she was younger, though it pretty well continued until, literally, the day she died, with just a little less depending on work schedules (for my sanity).
Basically, when she was probably 3 and under, us kids were all in school from 9-3. My mom, however, was a SAHM for that time, so somebody was almost always home with her.
For her first 6 months of having her, I was in school across the street, so myself, brother, sister and cousin would all come here during lunch. She got out to play basically the whole lunch hour (or however long it was). Then we'd get home at 3, and she'd pretty much be out with us from 3 til bedtime, with a break for dinner/homework. There was also an hour playing before school, and then fetch/backyard/training time while we were at school.
However, none of that was structured activity. We'd run around with friends, she'd follow, etc.
After those 6 months, until she was around 3, we went to school further away, and did not come home for lunch. So that lunchtime hour/whatever was gone. My mom was still a SAHM, though, so she had her.
Summertime she was with us outside whenever we were doing a dog-friendly activity.
After she was 3, mom went back to work. So from 3 til 9ish, she was home alone during the days. (Except for short stints that my dad wasn't working, or whatever). Basically, it then went up to 2 hours before school of exercise when possible (during HS, I was in band super early 2x a week, so it didn't happen those days).
After she hit 9, there was almost always one of us home with her again, as we graduated from high school. So she'd just do whatever we were doing.
As I got older, it went from "run around with me outside" to twice daily 1-hour walks with my sister, and then a 2 hour hike/swim with me. During the winter time, "swim" changed to "play with the ducks", with her sometimes jumping in the water before I could stop her.
All that to say, probably 6-8 hours of running as a puppy/young dog, and then 4-6 hours of structured activity once she hit 3 or so. Plus playing in the house whenever she wanted, and running in the backyard whenever she wanted.
I'd say that was average 4-5x a week, with the walks with my sister being 7x a week, adding an extra walk if I didn't get to hike/swim her that day.
Though, she was an easy dog and got the exercise because it was just as easy to bring her with
As far as what she *needed*, as long as she got the two one-hour long walks with my sister, plus playtime in the backyard, she didn't drive me insane or try to eat my ferrets.
ETA: She did get much more exercise during the summer. Because **** winter. I'm also fairly sure if we didn't get her used to so much exercise as a puppy, it would have been easier. Also, if I could put up with whining. But I'd rather her be dead tired and not whine.
