Thank you staffs I can't really comment about stamina with regards to working at night. To date I've only ever had him out a few hours at a time, as both of us are still learning the lamping business. That said, in the day time, he never ever gets tired and it seems to me that he can just go go go endlessly. And hardy .... well what can I say? I joke that he's coated in teflon Out in all weathers, on all kinds of terrain, through trees etc., and is always up for more. I love my whippet