I walk mine for just about 3 miles one day at the weekend .. and i walk them once every day for an hour in the evening.
Thet normally spend most of the day outside unless its very cold,... then getting them out is an issue..
they tire themselves out playing.. and race around for about 2 hours a day. They are pretty fit.. and can definitely out walk me!!! I would need someone to take over after the 3 mile post , to walk them another 3 !!!!
Oh dear,,, i must get fitter, lol

Hadn't really thought about this to be honest but I have noticed that both of mine have been shattered in the evenings since OH has been trying his hand at blind retrieves with them both.
I think because he has them working and concentrating when they are out it tires them.
Molly has loads of stamina and very rarely tires (I think she has duracell batteries ) but Charlie (being a bit younger) has only recently had her free running exercise "upped" and she is tired and sleeping for longer in between.
My two generally get lots of off lead exercise and I can definately tell if they have not had enough-they pester the life out of each other (and me) in the house.
Whether it's my fault for making them used to it I don't really know but I do know that I love the walks, just me and them whatever the weather

Never really thought about it. I take mine out because I love being out with them, but the lenght of the time out varies, sometimes we're out (like yesterday) for 4 hours other times an hour. I don't think I'm stamina building, as Skye likes mental stimulation too, Reah couldn't care less, and Bruce just does what Skye does (he's focused on her), however when we're in they become coach potatoes , until I say' right lets go'

I've never really thought about it either, it just comes naturally to spend as much time out and about as possible. We tend to do approx 2 hours and no idea how many miles we cover as a lot of it is doubling back on ourselves. We try to vary the terrain as much as possible and the dogs probably cover about 30 times the distance that we do. We also vary the speed a lot and try to build a bit of training etc. into it as well. That said my dogs give me no grief at all should they have to totally miss their walk for any reason. They're always up for an adventure and I'm not sure that I have ever tired them out.