>>14451732Perfect IVs isn't usually something that is possible, but I usually shoot for 30+ in critical stats (ie. speed and attack on a Sneasel) and 25+ on anything that is going to impact my efficacy (usually HP and defenses).
Most pokemon usually have one 'dump' stat that you can neglect entirely though. It's usually either attack or special attack, but sometimes speed is no big deal either on really slow pokemon who aren't going to be scarfing and as such, don't plan on outspeeding anything relevant anyways.
Breeding tanky mixed attackers like Swampert is truly hell though since you want perfect IVs all around on them since every stat is critical. Even speed was important when I bred my swampert in 4th gen since it actually outsped a few pokemon in OU.
