i must admit that before joining COL i had never heard of the 5 minute rule, and i know that i walked my collie cross much more than that when she was a pup. However, she was already 11 when i had Taz, so Taz only got slow walks when he was a pup and probably not too long (as Kelly refused to stay at home
). However, when i had Kira (lab) i did try and limit her walks to prevent too much strain on her joints.
Better safe than sorry, but as with everything the odd longer walk shouldnt hurt (unless it is hours of course)