This is a hard one to call as he obviously can't go on forever,but his passion for the game is stronger if anything,so who knows?
He may well decide the 20th title win will be the time to walk.No way do i see them winning the champions league in the near future.At the moment the creaking Ferdinand,Vidic and Giggs are bailing them out time and time again and they will all pack it in soon,as will Carrick in midfield.Rooney is hit and miss and Van Persie's goals have dried up,he is pushing 30 and due a major injury if his record is anything to go by.
He is hoping Jones,Smalling,Cleverly etcetera come good but i have my doubts they will be as good as the prior rag teams.There is no real money to buy big anymore and we are improving,in spite of this season,so to go out with the 20th title might just prove too big a temptation.