Up until comparatively recently, I consider Fox my best character. All of my friends had trouble matching his speed. The first tournament I entered, I got away with that for a couple of matches before I ran afoul of someone who had my number. Added to that, when I read up on Fox, I realized that I knew absolutely nothing about Fox and stopped using him.
Basically the same story with Marth, whom I had considered my alternate character.
It was then that I started using Young Link seriously; he had a lot of interesting moves I liked and nobody else I knew used him. (I hate sharing characters.) I improved plenty with Young Link, but did poorly on my second tournament, mainly owing to my inability to finish opponents.
Over the previous summer, I learned how to wavedash and picked up Luigi as my main, while keeping Young Link as my alternate and imroving on my L-cancel, as well as using a wide varietly of moves straight out of his shield.
The day before my most recent tournament (yesterday), I played against one of my more experienced friends; he observed the style of Young Link that I played and suggested I try his older counterpart. I did, and I liked him due to his superior reach, recovery, and ability to kill with his ^B, which I liked to use out of my shield. I now had three characters I could use.
The day of the tournament, I got 4-stocked twice as Luigi in warmups, which pretty much ended my use of him. Throughout the tournament, I could never really decide wether to use the older or younger Link. It really didn't seem to matter; I almost always lost by one life either way.
As of now, I usually switch between Link and Young Link every other match. I'd consider myself equally good with either one.
This topic probably didn't call for my career's story, but oh well. First day on this board, consider this an introduction.