Should Gatland leave Wales after the 2019 Rugby World Cup as expected, then Wales' visit to Twickenham this month will be his last in charge.
Three Six Nations titles in six years during 2008-13, including two Grand Slams, plus a Rugby World Cup semifinal appearance in 2011 have cemented his status as the most successful Wales coach of all time.
Those achievements, more wrongly than rightly, have been recently overshadowed by criticism of Wales' struggling attack and failure to defeat Australia, New Zealand and until recently South Africa.
Yet compare where Wales stand now with January 2008 and Gatland has executed a phenomenal transformation.
"We're a strange old bunch in Wales. He has been the most successful coach hands down," said Martyn Williams, Wales' most capped back row forward with 100.
"I think he said at his first meeting, 'from the outside, Wales look a bit boom or bust. I want to be competitive consistently.'
"I think he's done that. We have a small player base and I think he has brought a mental toughness to us that wasn't there before. His legacy speaks for itself."
"He has grabbed Wales by the scruff of the neck and given us a sense of identity, a game plan. He has turned us into an incredibly professional, fit, physical team," said former Wales centre Tom Shanklin.
"But it has not all gone to plan. There's a clear change of philosophy now in terms of how he wants the team to play. If you look back, that maybe should have happened three years ago. The highs, however, massively outweigh the lows."
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