I think he'd give us a good 5-10 years.
He left Porto to take over a unique opertunity at Chelsea then left Chelsea because of Abramovich, then he left Inter to take what is one of the biggest jobs in Football at Madrid.
After Madrid, aside from Portugal who he want's to take when he is in his 60's, who would be there left for him to manage? Everywhere else would be a step down again. The only other prestigious jobs left for him would be places like.....
Milan: Perhaps but Italian football would have to pick up again for him to be drawn away from us.
Bayern: Bundesliga might appeal to his collection but not much else.
Barcelona? Wouldn't put it past him but where will they be in 10 years? As a club they go through periods of success.
I can't think of anywhere else to be honest.
Mourinho has said he doesn't want to manage Barcelona.
I've said this time and time again though, once he comes back to England he'll be here for a long time because he's always said this is his 'home'. He loves it here and his next job will be a long-term one. He wants to manage the Portugese team but I think he's said he doesn't want to do that until he's at least 60 (12 years from now), so as you've said where else is there for him to go? If you look at the reasons for him leaving his other jobs;
Benfica - Chairman wanted a different manager
Leiria - Lead them to their highest ever league finish and was offered the
Porto job; you're hardly going to turn it down.
Porto - Did all he could with them. League titles, UEFA Cup, Champions League, Portugese cups etc.
Chelsea - Falling out with Abramovich. If Joel Glazer suddenly brought in a director of football against Ferguson's wishes, how do you think Fergie would react? What if he bought a £30m player from Milan who Fergie didn't want, but bought him anyway?
Inter - Lead them to their best ever season, was offered arguably the biggest job in football. Repeatedly said he didn't like Italy and hated the Italian media.
He's clearly number 1 for the job. Fergie will have a big say in who takes over when he steps down and he's a known admirer of Mourinho.