The Gaming Den

I should definitely know this, considering how long I've been around, but:

With items like a ring of blink and a ring of invisibility, when you activate them, they only last for 5 rounds and 3 minutes, respectively, then you have to activate them again, right?

Yeah it's a standard action to activate such an item, and you do have to keep activating it constantly. Though I find that a bit distasteful in the case of a ring of invisibility.