We've a large garden for the size of our house, but its not massive. The dogs tend to potter about and perhaps have a few minutes running laps before wanting a rest, quite often they'd rather go back inside to rest on the sofa than stay outdoors but depends what the weathers like, its great to have somewhere safe for them to run but they get there main exercise on walks. Were on clay soil and its not very usable if there's been a lot of rain it looks like a paddy field, often its quicker to walk them round the block than clean the mud off in winter so think we'd survive without a garden if needs be.
Our dogs go out in the garden quite alot, to go to the toilet, to sunbathe, to run round and go searching round the shrubs and trees. They still are walked once a day for about an hour off lead down the fields.