Na I think it's fine. Sure if you want to use what you have then you'll need to take the time to farm for those cores. Not too hard to do. I mean I've personally haven't been playing much since I'm currently playing wow(which is much more of a grind destiny would ever be). Still using the same weapons and armor. It's a waste of core to infuse if it's only giving 1 or 2 power level increase. 3 still not a good idea but 4+ is worth the use of cores. Now currently what will make a change to my power level is my boots. So I'm expecting to get them at 6+ power level (once a pair drops)