Collector Score "HODLer" Bonus
Since the collector score is meant for rewarding collectors instead of flippers, for the collector score, add a bonus for either each moment's length of time held or the weighted average holding time for the entire collection.
For example, S2 common moments are worth 12 only. If you've held the moment for 1 month add 1 point bonus, 2 months add 2 point bonus, etc. That will give an incentive for "HODLing."
Or if the average holding time of your entire collection is 1 month, give a one point bonus to each moment, etc.