Well I've been collecting those (mostly PVC, few resin) figures for over 10 years now, so I have hundreds, not counting gashapon (I have a lot of those too but they stopped being as popular some years back).
I have relatively few out, and they are overcrowded into 3 "smallish" (similar in appearance to the popular Ikea Detolf but not by the same company, as I could not get those in Hawaii) glass display shelfs. I have 4 more of those shelfs but as I don't have enough bedroom space I never unpacked them and they are lying flat, unassembled in the yard. (I am terrified what I will find when I try to assemble them someday, as the packaging is all termite-eaten and rain-soaked).
I also have figures all over my bedroom, many covered in dust and others in those small soft plastic Japanese display cases (some turned yellow because the sun hit them so I'm sad now). Those mini-cases are stacked everywhere: on top of the Detolfs, tables, bookshelfs, and even the floor.
...That was the state of my collection about 5 years ago.
Since then I just continue to accumulate figures but with nowhere to put them, they just stay in the brown shipping boxes forever! Many times I have no idea if the figures are even inside because I never opened them. I just assume I have that figure. Sometimes I even forget what figures I bought already and then I don't know if I have to buy another one.
I used to buy 2 or more copies of every figure I liked but I stopped doing that when I ran out of room. Now I only buy 2 if I really, really, really like it.
The stacks of unopened brown shipping boxes go up to the ceiling and eventually spilled out from my bedroom into the corners of the living room and other guest rooms, and even outside garage-like storage (however, I am afraid to put too many of them in there because the storage houses get really hot and are super dirty).
But I don't document anything and the last time I tried to take pictures of any of my figures was back when I had less than 20 (because I started out with garage resin kits that I poorly painted myself). Before that, all I had was the Kaiyodo VOOT figures.