What is your Player Leveling Up Strategy?

Curious with leveling your players up what Strategy people are using?

Do you just level up across the board with every player on your team or wait till you get a Rare or Epic player?

Many of the games require 25+ Levels to proceed to finish the final stage of the game, so it’s pretty much dictating who I Level up.

Sure hope the Uncommon players I’ve leveled up to 25 now that I’ve replaced with Epic/Rare ones, can be traded for collateral somewhere else??? 

Also, it would be nice to know your total currency needed to Level up? I have run across some players where it lets you slide to the other levels and shows currency needed, but not all players.

EA_Blueberry: Added text to post title and sticking the post for a weekly discussion