End of album/Vault explanation?

This is my first time being gold locked (almost im one off 🤞) and im confused on what happens to the extra stars and stickers when 1) you completely finish the albums and 2) if you dont use all the extra stars you had on vaults. Is it best to give away all your extra stickers or gather more stars and use all your stars for vaults? Or would it be ok to not use them even when the album is over? Should i open the pink vault, if not when? Would any of this change if I don’t completely finish the album?

Sorry for all the questions but im pretty lost honestly, and any explanations or more info on albums, vaults, and star completions would be really appreciated 🫶♥️