Have you seen the same post boosted in your timeline again and again?
Mastodon does automatically hide repeated boosts, but unfortunately it is set to allow repeats of boosts after 40 other posts have scrolled through your timeline.
There is currently no easy way for admins or users to adjust this number as it is hardcoded into Mastodon's server software. If you're comfortable using Github, you can vote for this to be fixed by giving a thumbs up at https://github.com/mastodon/mastodon/issues/18693
