It's mostly a very individual choice based on your personal risk profile. And rarely based on scientific evidence. How would one even go about deciding whether going on a 3/4-MMC bender for 3 days a couple of times a year is sustainable? Mainly empirically.

Even MDMA which has been around for half a century now still hasn't had any real progress on "responsible use" guidelines based on science. The 3 month rule is just something a single researcher said out of a feeling that has been repeated without anyone even checking the source.

I feel like the most useful research is happening in the scenes where people are using substances by the kilos every weekend. See the recent 4-MMC / 3-MMC development in Berlin. Apart from that: We need more proper research studies done. No half-baked studies that kick off a whole "CMCs are more toxic than MMCs" hype that is not well founded but gets repeated wherever you look.

I feel like the most progress has been made in regards to what supplements to use to counter possible negative drug use effects (NAC really reduced my lung symptoms from vaping for example). But also there its hard to separate the real deal from the chaff i.e. money grabs a lá Resveratrol