This has been bothering me for some time, and I apologize for any mistakes here.
What I'm looking for is another word for discretion without possession. It's almost like saying the phrase "up to you".
I don't care about the color of the car, so that is [your decision/up to you].
What you choose to wear is completely [your decision/up to you].
I could say "That is your discretion" but I'm looking for an adjective. I was thinking of the word optional but that almost implies that the object is unnecessary.