hey i was wondering when you guys would recommend getting a tranny fluid flush/change? i know BMW claims it's a lifetime fluid but i've read in other places to do it at 100K miles and other places not to bc it could remove sludge that is covering small leaks?

any advice?

Welcome to the forum. Not knowing year car's stats, we can't really offer advice on that. If we did, it would probably in vain as this has already been a widely discussed topic. Navigate yourself to the DIY section and you will see the info you need to make an informed decision.