A friend of mine says that slotting any enhancements and building IOs is useless until 22. In fact, he says that doing so will actually disadvantage you, because you are wasting money. He sells every enhancement he gets, and all of the salvage that doesn't go into IOs for damage, accuracy, recharge, endurance reduction.
Personally, I like having my powers do more before I've played for days.
Is it really that bad? Is he just power-gaming, or is there some sense in what he says?