When you attack with ground units or air units, I would recommended bring some lurkers along. For example, if you attack with mass guardians and devourers, bring some overlords and load them up with lurkers. Then when you attack, kill the turrets, cannons, or spores with the guardians, and kill the overlord, science vessel, or observer with the devourer. Now, just drop your lurkers and let them attack buildings. They do lots of damage, and it does splash like damage too. So, it's good for attack small things. I would recommend dropping them not in the mineral patch but beside it or very close to it. But if you are attack with hydras, zerglings, or ultralisk, also bring some lurkers. The hydras, zerglings, or ultralisk normally gets the hits, so just walk your lurkers in, and burrow. This strategy helps me a whole lot, I hope it will help you.

CreepColony's Opinion: Lurkers will be good for killing enemy ground troops that are attacking your army.