>>16347726with almost all pokemon you don't need or want 6ivs
for instance if you want to breed a kangaskhan you are only going to want perfect ivs in hp, attack, defense, special defense, and speed.
there is no need to have perfect ivs in special attack because kangaskhan never uses special attacks. the only time you actually need all 6ivs is if you are making a mixed attacker. getting 6ivs is exponentially harder than getting 5 though.
for some pokemon you only need four. ferrothorn for instance doesn't need special attack or speed. in fact it's good to have ferrothorn be as slow as possible because it often uses gyroball which does more damage the slower you are.
klefki is another pokemon that sometimes only needs 4ivs because it doesn't need it's attack or special attack at all if you are running it with foul play. foul play is based on your opponents attack stat instead of your own.