Richards, who twice toured with the Lions, has now served his time and will take charge of Newcastle Falcons in the Championship.
"I have huge regrets and I would never, ever do the same thing again," said Richards.
"I have the same ambitions to win things and the same passion but I have huge regrets and I understand exactly where the boundaries lie. I would never step over them again.
"If people want to say something, they can say something. I have done my three years. If they feel I should have got more then so be it. Some people feel I should have got a little bit less, so be it. I was given three years and I have done three years."
The Leicester Tigers legend has a track record of turning clubs' fortunes around, having brought Harlequins back to the top flight. Now he is determined to repeat the feat in the north east.
"In terms of personality, I have the same ambitions to win things and the same passion. Nothing has changed in terms of my appetite and what I want out of the game," added Richards.
"Now, to be back in rugby, I am loving every minute of it. The banter in the changing-room, the camaraderie, the team spirit.
"I have not been part of that for the last few years and I missed those sides of rugby. It is nice to be part of it again.
"It has been your life for 20-odd years and you have it taken away and you miss it straight away. But you serve your three years and you get straight back into it and it makes you realise what you have missed."