Before my PCS, I would certainly feel it go to my head slightly if I had even 1 cup of coffee. Nowadays I know that whatever it is doing to stimulate my brain is bad for it, so for me even 1 cup is too much right now.

I was never that into coffee anyway, I guess if you really love coffee or would feel stressed without it it might on balance be worth having it every now and then. But if you can take it or leave it, I'd just cut it out.