Is this IF ok? Or is there a better way?
How about:

if (!defined("MEMBER_LIMIT") ||  MEMBER_LIMIT == 0 || $memcount &lt; MEMBER_LIMIT) {
  // will do something
}
else {
  // will do something else.
}


The key is to look for both complementary (multiple items that accomplish the same thing by different means) and contradicting criteria (which would interrupt your desired flow of logic) in if statements