To necro this a bit, if you can work things out so that you are wanting to catalyze an IO, and you've already got that IO, catalyzed, slotted on an alt, it saves you the cost of an unslotter to unslot the catalyzed version, slot the uncatalyzed version, then catalyze it, leaving it in place. For example, if you have an Acc/Dam Thunderstrike, and your character has Thunderstrike five-slotted in a power, including the Acc/Dam IO, then just unslot that one, slot the regular IO, and catalyze it in place. It's not a big saving, but it can add up over time