As discussed previously, both Starwood Preferred Guest (SPG) and Marriott would be making their annual adjustments to their respective hotel charts on 6 March 2018. More details can be found here for SPG’s changes, and here for Marriott’s.
If you’re currently looking at Starwood hotels which are going to go up a category, there’s no time like the present to pull the trigger on that redemption booking. However, if you’ve noticed that a certain hotel you’ve been eyeing would be going down a category come 6 March, then it’s best you wait until then to perform the booking (probably night time in Singapore since the changes take place around noon in the States).
Hopefully you’ll still be able to snag those award nights at the better rate pre/post devaluation!