You decide for yourself, but when I logged in today to my SPG account it said I needed 45 stays or 50 nights to maintain Platinum status. In the past it was 25 stays or 50 nights to maintain Platinum status.
See this Flyertalk thread for more details. Anxiously awaiting feedback from William on Flyertalk.
If the new requirements are in place, you’ll need to book more stays on SPG.com if you had planned on the original 25 stays to maintain your Platinum status.