Sigh...
< rant>
So I party with my roommate all the time (occasionally with random other people) but usually it's just us. So far (and we only play when we're both on) he's managed to obtain 16 iron gears while I have obtained 0. This is through about a week of T2 runs that are mostly just me and him. Some how the iron gear just never gets randomized to me :(. It's not that I haven't received my share of 2 star+ materials, but I actually need iron gear to upgrade my autogun (whenever basil gets around to restocking the needle shot recipe) and he only needs them for one of the later tangent weapons he plans to make T_T. I've bought/traded 3 of them off him, but I still haven't gotten one from a drop myself. I even soloed 4 levels of mechanized poison monsters one night b/c he had forged and didn't have enough energy to follow me and I wanted to see Basil and I didn't get any iron gear drops :(. What's with this one sided iron gear drop rate TT_TT.
< /rant>
Solo. T1 and 2 are both pathetically easy to solo, and if you're aiming to get mats via drops, it's much better than going with someone, unless the person doesn't mind just giving you the material. Any time you're with friends and after specific materials, you should set up an arrangement beforehand.
I had my friends bouncing me their critter carapaces back when they were hard to get, for example.