Telling sites to reduce the number of entries in a feed and telling users to decrease the refresh frequency is a bad idea for sites that update frequently. Very few self-hosted rss readers allow for per feed refresh rates (freshrss is the only one I've found that does I think) so to capture everything on sites that update frequently but have tiny feed sizes I have to run separate cronjobs. That's after asking them to increase the feed size.

https://www.earth.org.uk/RSS-efficiency.html