Gear and collaborators
Your equipment. Both kinds run out, in different ways.
Talent does the work. Gear and collaborators are what make a song sound like nobody else made it. They are also the two card types that do not last forever.
Gear wears out
Instruments, recording kit, the clothes. Gear is where most of your uniqueness comes from, and it wears down the more you write with it. A piece used in every session fades faster than one saved for the songs that mattered.
The Surf Green Electric
Vintage Amp
The Look
Sixteen Magic Pads
The Wall of AmpsCollaborators have a session count
Each gives a bonus and a limited number of sessions, then leaves. Famous ones have more sessions and cost more, so the price per session is closer than it looks. A big bonus with few sessions is for a song you are trying to make special. A modest bonus with plenty of sessions is someone you work with all the time.
The Fill-In
Harmony Queen
The Hit Whisperer
Living Legend Feature
The Sound GodWatch the genre on it
Gear often carries a genre. It is worth a lot when it matches what you are recording and nothing at all when it does not.
When they run out
Used-up cards leave your collection, which is not all bad news. The thing to avoid is everything running out in the same week and dropping you back onto plain cards.