I believe they have a limited shelf life & any surviving ones are duds by now, but 90 days is an underestimate of the trigger life.
OTOH, refurbishing one that you know is going to work is a lot easier than building a new one from scratch.
You don't "refurbish" an atomic trigger. It's not a mechanical part. It's a radioactive element that decays rapidly. That decay, however, also means that it doesn't last very long before it becomes material that is non-useful to reactions.
You can replace triggers, but you don't "refurbish" them because there aren't any parts to fix. You simply need new material every 90 days or so.