basically whenever it costs you less % of the pot than the chances of you winning, you have a pot equity edge and you need to push it.

for example, you have a nut flush draw against 4 opponents. you have a 35% chance of hitting. assuming these people are loose, and the board is coordinated for straight draws, almost all of them well call. when you bet, and all 4 of them call, you contribute 20% of your bet and their calls. but you will hit your flush 35% of the time. you have a 15% edge so you should push it.

pot equity is for being aggressive and betting, while pot odds and implied odds are for you being passive calling.