The hooker's frosty relationship with the press and extensive disciplinary history means he has not always received the credit he perhaps deserves.
However, the fact is he remains his country's most capped man in his position, having made 93 Test appearances.
Form woes have also led to regular calls for Jamie George to be made Eddie Jones' first choice in the number two shirt and the Saracens man will get to stake his claim this summer in South Africa.
Hartley has been ruled out of the tour in a bid to help ease concussion issues that have sidelined him since March's Six Nations defeat to Ireland.
Returning for pre-season is now his goal and the New Zealand-born star says the chance to reflect has given him a fresh appreciation of his desire to play the game.
He told Sky Sports: "As soon as the decision was made for me not to be involved for the tail end of the season, it took a lot of pressure off.
"Rest has been the best thing for me. The mental pressure has been taken away by not trying to get back early, not trying to make it back for a tour, for end of season games.
"The best advice I got was to stay active, which I have done, but work within a framework. I've still got limits that I know I can go to and I'm actually looking forward to pushing the boundaries a little bit and getting the blood pumping."