Fans need to stick to their teams no matter how much they're sucking now. You'll feel much better when they finally find success. Bandwagoning only gives you temporary happiness.
one primary team, unwavering support for them no matter who they play or how many times they lose.
one secondary team if you really like a player in that team or just like that team in general. (like for me i like liquid coz they have the goat nAts)
and in internationals you can always support the team from your region, especially when your team is not playing that match.
you can always be new fans of teams like edg who just pop out of nowhere and you cant help but root for them. but if the time comes edg play vs primary team. you have to choose primary team.
if you follow the above rules, you are not a bandwagoner, loyalty is of utmost importance.