I didn't exactly jump on the game as soon as console came out myself, mostly on account of not having a venue/scene at that point. I want to say I've been playing for about a year and 3 months (give or take a couple months or so) but I can't be entirely certain. That said, I've gone through plenty of character changes in adapting my play, so here goes...
My first team was K'/Terry/King. I messed with the order, but I liked the characters too much to really experiment with anyone else. People told me King was my best character, so I settled into habitually using her on anchor for a bit. Then I found out
why people play her on point, so I made the switch and
instantaneously started doing a LOT better with her against my regular opponents as a result. Somewhere in the midst of this period of time I discovered that DLC characters existed, and 98/Flame/EX/Classic/etc Iori took the spot previously occupied by K'. I played this team for a good long while, then suddenly a wild Shen appeared and started doing HD combos for me before I figured out how to efficiently play him without meter. He made for a startlingly easy anchor, my whole gameplan relied on waiting for them to do something I could punish with a cl.

and doing more damage in one go for less meter than I'd ever relied on before. As a result of this I became obsessed with learning HD combos, and I soon perfected Shen's 2-bar variants. My Iori eventually found one too, and along the way I dabbled in EX Kyo, playing him casually just because I could hit people with his

rekka

rekka loop and laugh maniacally while setting the entire screen on fire with the Neomax. My Terry (who I still played occasionally) also leveled up to "can actually sometimes HD for 0/1 bar with" status, but my tournament team was King/Iori/Shen. Then...
Something crazy happened. I realized I was hopelessly infatuated with Mature and Vice, and remembered the vision that popped into my mind back when I saw preview images of XIII, back when I was still a casual who only played games against his equally lacking brother, a nobody with no skilled opponents to compete against and learn from... That vision was of a team, and that team was King/Mature/Vice. I'd practiced the latter two a bit already in casuals by this time (to the point of picking up Vice HDs) but I couldn't bring myself to commit to the team yet on account of having no luck trying to master Mature's HDs. The day I finally discovered how to properly drive cancel from her

metal massacre (and thus perform her legitimate HD) was the day I decided it was time to stop messing around, and play the game the way I'd wanted to play it the day I found out it existed...
So then, I struggled. My existing tournament team had reached the point of having recently earned me a delicious 2nd place at my local weekly after an intensely satisfying grand final that included a bracket reset... This was the closest I'd ever come to taking the weekly fight money from anyone before, especially considering it was my rival who happened to be my opponent that day. But instead of continuing to play that team, I fought to conquer Mature and Vice's respective neutral games. Learning to fight people with these characters was extremely difficult (especially Vice, realizing I couldn't just throw fireballs all the time from full screen was a huge issue) but the team was so beautiful that I swore an oath to never play King, Mature or Vice unless I played them together as a team. Slowly but steadily, my skills with Mature and Vice grew stronger. My Terry had moderately consistent corner HDs at this point, so Terry/Iori/Shen became the alternate team I'd play in casuals.
Then a few weeks ago, my oath broke. It was a losers' final at our local weekly, and I'd become so frustrated with losing so utterly consistently to my aforementioned sparring partner/rival that my love for the team no longer mattered. I decided Vice wasn't pulling any weight, so I switched her out for Iori after the 1st match in the hopes that it'd give me the win I was so hungry for. It didn't, but in doing so I managed to finally recognize that my tunnel vison of love for that one team had been stunting my overall development as a player. So I got back on track, and put the team aside in order to seek improvement in my game as a whole, with the basic goal of improving my win/loss ratio against the man who had broken my oath. After a few sessions of no luck, this very night I happened to make a breakthrough in understanding my mind's interface with the game while playing. I was so happy for having actually learned something that I didn't bother to spend the effort in applying it just yet, and stood up from that 15-2 "loss" more proudly than ever before. We played a ft10 later, I picked King/Shen/Iori... and I started 3-0 against him. It ended up 10-7 his favor, but as of now I have long-lasting confidence, not just in my ability to play the game but also in my capacity to improve at doing so.
So yeah, I'm gonna run King/Shen/Iori as my main team again. Before tonight I was lacking a meterless game with Shen (when I played him before he was firmly locked into the anchor position due to not being able to hit anyone with more than one HD combo) but now I'm confident that he can play mid when the match calls for it, and if I can have the edge against my rival's Saiki with King, I can do the same against anyone else's point character.