Which material will you use them for?
Personally, since I need both feathers and gears (and some bronze mats, but those will be on upcoming lotteries), I looked at event shops (and lotteries) for Christmas this year and all events of next year, and for me there was only one conclusion:
Use them all on gears.
The other materials just aren’t as rare if you include lotteries, and nearly every (or every?) event from now to end of March has feathers in their shop, but only KnK has gears until then.
After that, JttW rerun and Apo events have gears as well, and early June will have them in a hunting mission, but after that it’s only like 1 more event shop until the end of the year, so pretty much a drought again.