Excellent thread and responses so far! I'll illustrate my sports card collecting. Green = heavy collecting, light green = light hobby/retail purchases, red = not collecting at all.
Some notable points in my collecting:
1991 - pulled an Upper Deck Michael Jordan SP1. Coolest card I ever pulled from my youth, naturally from picking from packs at the bottom of the box at a Shell gas station. This is also the year I moved from rural Illinois to Chicago.
1993 - I attend my first and only NFL game, a preseason game at Soldier Field where the Bears beat the Cowboys 23-21. I remember a concessions guy walking around with subs and it RULED.
1990s - don't remember when but my local card shop had a quarter machine to get cards and I always used my pocket change for a couple pulls. Got my 1986 Topps Jerry Rice rookie from that thing. I ran 6 blocks home in utter excitement.
1998 - I moved to Iowa.
1999 - I moved the hell away from Iowa right back to Chicago. Technically the Bulls team was blown up the previous year but MJ was still appearing in products for the 1998-99 run. The lockout served as the death knell for me and basketball.
2000 - I attended the Chicago Sun-Times Sportscard Convention at the Rosemont Horizon (now the Donald E. Stephens Center). I paid $150 to get my authentic NFL ball signed by my childhood hero Joe Montana. My brother thought he was kind of a jerk lol.
2001 - I moved up to Wisconsin. Thank goodness the Bears went 13-3 that year.
2002-06 - I'm in college and no time/money for cards.
2007-10 - student debt is crazy. I join the Beckett boards for a second time with this current username. Forgot the password to my old account, MajerleKerr0925.
09/14/2008 - I watch the craziest game at Miller Park in Milwaukee ever. The "home team" Houston Astros take on the visiting Chicago Cubs and Carlos Zambrano throws a no hitter as the Cubs dominate 5-0. I still have the ticket stub to the game. It's the height of hilarity that the neutral site was Miller Park as we refer to that as "Wrigley North".
10/28/2008 - I complete 1999 Topps Finest Refractor set with Daunte Culpepper the last to join.
2010 - I decide to focus my collecting primarily on Topps Finest, looking to build all the base sets I can.
2015 - Topps no longer has an NFL license
3/3/2015 - I complete the 2000 Playoff Absolute Leather & Laces set. It's a full memorabilia set and the last two added are Tim Dwight and Bobby Engram. The former accidentally found on SCF after randomly scavenging flickr/photobucket accounts and the latter a bit of luck from a Bears super collector selling his collection on ebay and willing to break off Engram.
08/03/2020 - I post in a thread recounting my hobby history and reading about fellow collector's journeys.