Always farmed every piece of equipment I have.
Sure you can buy a frame instantly, but what's the taste in that? The game literally revolves around collecting every frame and weapon and doing so fill me with big satisfaction.
Moreover sometimes you get to do quests to unlock them which can be quite interesting and fun. For example I really appreciated the quest of Octavia and Umbra, and recently the one of Yareli.
I know that farming for plats is much more efficient, and in the end you always someway "farmed for it", but imo is not the same thing, because you buy someone else achievement, you don't make your own or earn it.