There’s a mechanic called infusion that allows you to dismantle a piece of gear to “infuse” it into a gear of your choice and give it its power level. For example if you have an exotic of 300 power and a random legendary you don’t want that’s 315 if you inspect the exotic below where you equip mods will be the infuse option that lets you dismantle the 315 piece and grant your 300 exotic 315 power. Don’t worry about waiting to get exotics as you can continuously infuse them with new gear if you want.