alan25, I think you'll find the offer will come early in the new year (once the total number of paid nights for 2014 is final). Your current status will remain until Feb at which time you would drop to Gold if you did not have the required 75 nights to stay Platinum. The offer to buy back your status usually shows up in late January or early February. I don't recall the exact number of points but 40,000 for Platinum (25,000 for Gold) seems to stick in my mind. In years past you could buy back your status thru April 30.
While I don't know for sure about 2015, I have no reason to believe it won't be available.
As bejacob states, elite buyback is offered every year at:
Silver, 7,500 points. As the main benefit of silver is 20% extra points and the status is awarded after 10 nights it's difficult to see how this is value. You'd have to spend $375/night during those 10 nights just to get back your investment via the 20% extra points.
Gold, 25,000 points. A lot more points, but for a lot more benefits. You wouldnt do it for the extra 5% points gold offers over silver, but if you mainly stay FS it's easy to see the value. Lounge access, worth say $20/night (2000 points) gets your investment back in just 12 nights. A suite upgrade can get it back in one, and I've always received at least 1 suite upgrade each year. This is definitely worth it for FS stayers, no question!
Platinum, 40,000 points. Now this one I struggle with. The main extra benefits of Plat is the extra 25% points over Gold and the 500 point arrival gift. I stay only at FS and have stayed 80 nights this year. The plat bonus (over gold) added 45,000 points, and the arrival bonuses 26,000 points. Thus the value over 80 nights works out at 900 points/night. To break even I need to stay 45 nights, butt-in-bed, at an average of $220/night. Fractional stuff, but worthwhile if you've got a big event planned next year, or regularly visit sold-out places where the remaining benefit of plat comes into play, the 48 hour plat availability.
OF course there's no guarantee Marriott will offer it in 2015, though it seems unlikely they'd not. They might increase the cost, and if they did that'd make silver even less attractive and turn plat into unattractive. Gold buyback is likely to remain a good deal for any regular FS guest, though...
I agree 100%. I get a suite upgrade (usually requested ahead of time by emailing GM or Front Desk manager) about once a year. In those instances I am getting a room that is usually $300-$600. I agree and think just one of those makes it worth while and especially when combined with the other Gold/Plat perks.