I generally find that you mainly have to keep track of a few key purple gear and raid gear. For purple gear, it's pretty much Carbantis, Stun Cuffs, Stun Guns, Thermal Detonators, and Holoprojectors. Whenever I'm looking at what I'll need for a character, that's what I mainly focus on. Outside of raid gear, those 5 are the main road blocks. Once you get to G11, you add some gold stuff and more rare pieces, but I usually only worry about gearing to G11 for most characters. Outside of that, you probably have everything you need, or can fairly easily farm it.