There are a couple of places near us where walking dogs off lead is pretty common. Ours has good recall so we let him off lead when in these places and he loves it. most dogs I see off lead seem to stay pretty close to their owners, subject to the occasional run around with another dog.
Since ours has hit teenager age, however, when he is off lead he does not always stay particularly close to us. For example, if we are walking in a wooded area, we will be on the path and he will go off running through the trees jumping over branches etc (and probably chasing the odd squirrel) so we can't always see him. He does still come back when called although we are not always sure whether he will appear on the path in front or behind us.
We have been happy to let him do this (in areas we know are safe, e.g. he could not get out onto a road) as he really seems to be enjoying himself (and people often remark on how happy he looks), so we only call him back to check in from time to time rather than making sure he is always right by us.
However, I very rarely see other dogs doing this, so I am now wondering belatedly if we should in fact be training him to stay closer to us more constantly, e.g. by recalling him very frequently.