Originally Posted by Overload

Not entirely true for collection/album purposes you should keep 1 of every 2* until you have their affection to 100%

That is a complete waste of time purely in terms of progression, but even as a casual time sink. The reason being that it is ALWAYS EASY to obtain those 2★ characters and fill out your album later. You should instead use your precious gifts on your higher star characters, because affection levels AFFECT character stats. if you're blowing them on 2★ to 100% and then selling them to make room in your inventory, you're doing it all wrong.