Old Part advice?

Howdy,

Hope you all are having a great weekend!

Doing a little work on the z today, and starting thinking of the parts that I have and what I might need.

Changing out my old door panels, finally put in my "new" ron's z's clock, which works as good as it looks! Changing out the bushings on the compression rods later today.

I starting thinking of evilbaying some of the extra parts I have around that I will never use, and then thought about some things I should start to gather as "spares"

I need your advice, I have a series one car, and I have slowly added spares that I thought I would need. The things that I don't have are the steering column upper and lower u-joints and the fuel expansion tank. I was also told that rear brake cylinders are NLA? Not sure if and when any of these parts fail or need to be replaced, but thought I should ask the experts here. Any advice would be greatly appreciated.

Thanks in advance,

Bob