I start using them as soon as they become affordable to stock up on, so like 3rd-4th Jim. I run from basically every wild encounter that I'm not going to catch before then. My team's experience comes purely from trainer fightss.
Wild battles are basically just a pointless time sink. They don't give you enough EXP to matter at all, and even if they did you never need it. I already play these games slowly exploring every area and talking to every NPC. I don't need interrupting every five steps on top of that.
I don't understand why anybody wouldn't use them.
