Wener

HI everyone, I am new to fotography/videography, but it is very intereting and there is so much to learn. :-) So through reading on this website I learn a lot of you guys (thx 4 that). I get you guys using negativ values on your picture profiles to have more flexibility in post. Would this not make it necessary to under expose a shot/video so it will not blow out later in post? I can't find any rule/chart so I would know how much to under expose, so it will be fine when working with the material? Maybe because I use the wrong terms to search or I am maybe not grasping something important? Can someone maybe please point me in the right direction (correct term used or adjust my understanding)? Thx