Battlemonkey, you are supposed to understand the purposes of those three flags, not for the sake of "you're used to." The only exception of those flags is /S , which is available for mirc to strip control codes only.

The /i flag, as you should already know, is to make the regex case insensitive.

the /g flag is to make regex greedy and global and search more than one match. Without the g flag, the regex will only return the first match it finds.

It all depends on what you do with regex, not all of them should be inserted with g flag. Again, not because you want to or you think they look "pretty" in the regex..but because in certain cases the /g is needed to perform required regex functions.