I just migrated from Blueskyfeeds where feeds held on to posts for 4 days, and with how small and niche a topic/community I have curated, sometimes there are only like a dozen posts in the last 2 days (which seems to be the limit for Graze). It would be useful for longer feeds that have lots of posts have their limit based on how long ago the post was made (current functionality), and shorter ones with less posts to hold on to posts either for a longer period of time, like 4 days, or hold on to a specific number of posts, like maybe 50, that wouldn't tax Graze's systems too hard. This way folks who only check their feeds for more niche topics every once in a while will have the ability to catch up on what happened over a longer period of time.