When should Michael Schumacher retire?

[herowassenna]

Schumacher was also very clear in his contractual requirements.
One of the major ones was that he would leave if Senna was ever employed by the same team.
And for all his success at Benetton, I never felt that Briatore ran 2 equal cars. There was countless times when driver had better equipment than driver b.
I respected Schumacher during his years at Ferrari because whether his work ethic, Brawn and Todt's obvious favouritism or simply because he could drive Byrne cars better than anyone else, he won for my team.
I never warmed to him because for all his ability, he seemed too controlled, maybe too teutonic.
I'm still firmly of the opinion that during the years 1995 to 2004 he was the best out there. But to qualify that, he usually drove the best cars against subserviant team-mates and lets be honest, his contemporaries weren't truly great.
The current field is the best since the 80's and they just don't hold Schumi in awe anymore.
Rosberg, as has been stated already, is not considered a great. A very good fast driver? Sure. Similar to Webber maybe?
I think Schumi came back because Brawn dominated the first part of last year and he expected the same again. But if you look back at 2009, Brawn didn't develop anywhere near to the pace of Red Bull or Mclaren.
Brawn succeeded because he had $200,000,000 of Honda money to develop a car for 2009 and forget about the heap of 2008 crap.
This year, Red Bull, Mclaren, Renault and now Ferrari ( after a Spanish kick up the jacksie) have out-developed the works Mercedes effort. To a degree, I'd say Sauber and Williams as well.
Besides the obvious aging process, Schumi has had the obvious handicap of no testing. I feel also that his ability was the sprint race scenario. Maybe he can't adapt to the non-refuelling skill set required.

Super Hans listed his contemporaries. The name Frentzen is interesting because although he won GP's he disappeared without a murmur. Yet when he was part of the Mercedes sportscar team, he was considered faster than Schumacher.