2008 -2009: Collected almost only North American Saturn and N64 games here and there.
2010 - 2014 : I collected pretty much everything and anything from the NES and newer, having somewhat more of a focus on N64, Dreamcast, SNES, and PS2. This was sort of my golden era of collecting as I used to hunt all the time and I often found tons of great stuff. 80% of my collection was built during this time.
2014-2016: My collecting definitely became a lot more focused since many of the games I'd been after for years were now in my collection. I started collecting a lot of PS1 and DS during this time, especially PS1. I also started making a push to complete my cartridge only games, mainly N64. I also began downsizing a little at this time, mostly for consoles I realized I wasn't that into. These include NES, Sega CD, some SNES, and some Genesis.
2017-present: Since the beginning of this year I have become somewhat of a non-collector; I still buy games and add them to my collection, but only ones that I know I'll play within a month or so. I almost buy no retro games anymore despite loving them still. I have downsized probably 20% of my overall collection since January, mostly the retro stuff and have began selling games that I play that I either do not like or do not like enough to justify holding onto them given what they are worth. I have also become way more of an actual gamer in that I love to play games way more than collect them which was the opposite up until this year. 95% of all games I buy now are modern games and I now do a lot of MAME and emulation now as well even if I actually own the game I'm emulating.