My two cents, Where we are at now going from 650 to 700 you should ONLY be infusing duplicate items that only cost glimmer or the one or two exotics you truly love (hence it being an impactful decision when infusing your gear). Any piece of gear that is higher light that you do not want to use should be vaulted to help light progression. Once you get to 700 this is where the infusion end game happens. But Nitro, what about that full set of Prodigal Armor I use? My titan looks awesome wearing this and I really would like to infuse this so I don't look like a space hobo. The time will come when you can play dress up again once you reach that 700 light. If your infusing every piece of new gear into old gear you will run out of cores fast. My rule of thumb is to infuse once I am 15 levels above my previous level on my favorite weapons and gear. The next time I will infuse my Skull fort is when I reach an overall level of 690. My favorite weapons were only infused after I reached 675. This is how I play. This is my opinion. Make Destiny yours while understanding the rules of the world of which you play in.