I have started platinum challenge on June 4th and I got time up to September end, as many said it's not exactly 90 days but 3 month + first month complete days. I have completed my challenge on 6th of August and instantly afternoon have seen my status changed to platinum. Few points I have observed, a) I had Amex platinum which given me gold and immediatly I enrolled for challenge, 80% time I got upgrade and in Westin property I was upgraded to Club category with club lounge access b) Aloft category I got upgraded to best available room which they consider as Suit c) Best experience I got from Fairfield in terms of very friendly staff and they arranged an elite night gathering. d) I always took PDF copy of my bill and tweet it to Bonvoy team to include fast which helped me many times as first time I seen it got delayed. e) I requested theWestin hotel Bonvoy team to update my stay and that night itself it got updated so it's better to keep positive and friendly terms with hotel where we stay. Now I think I can go for Titanium ��