I can document my journey right now. One team only as I have found multiple teams distracting, time-consuming, and mistake-prone. Have you ever seen the card you've waited for for weeks at a great price and then in your excitement buy it now only to realize you are in one of your alts? One team, because I have only one goal and it's not to have 'fun', but to win PL without spending money. (I do have fun, though). Not only that, but if I want a trophy
I have to win in the first game year! Winning PL in year 2 is a second-rate achievement--no trophy for you! To do that, I need to raise 8 million points and buy when prices are low which means doing
nothing** with my main team for a long time. Building up my tournament team and then spamming the appropriate quick tourneys as often as I can is a strong move. The goal here is to win 100 packs a week between that and freebies like twitch drops. 3500 packs after 35 weeks is roughly 3.5 million points. Another 3.5 million comes from flipping cards. Finally, if I do it right, my main team will still be in rookie after 35 weeks, and buying the high-power, high-eye team and pitchers with high stuff all at once, I can make another million in achievement points by the time diamond league is reached 7 weeks later. That'll leave me a tiny window to reach and win PL before time runs out.
**Some people have figured out how to score and give up 15 runs a game in rookie and never promote, nor even qualify for the playoffs, but I'm not planning to do this, although teams I've discovered doing this have not been banned, so I guess it is OK to do this.