In light of the ich problem I'm having I've come to the conclusion that I should have a quarantine tank (a little bit late, but...).

However, my question is, should I have a quarantine tank set up 24/7? In case one of my fish randomly gets sick/injured or in case I suddenly find myself with new fish? Is that what most fish keepers do? If so, how big is your quarantine tank and where do you keep it? Do you have a separate set of supplies for the Q Tank? Like siphon, net, etc?

Better late than never! You're bound to make a mistake or two when coming into the hobby. We all learn from our mistakes.

Yes, definitely have separate supplies - anything that comes into contact with the water/fish, at least. And do maintenance on your quarantine tank last, if, for instance, you're doing water changes on all your tanks.