Not a stupid question at all. Suppressive therapy is meant to taken on a daily basis. You need to have the medication constantly in your blood for it to do its suppressing job. Taking it only when you feel an outbreak coming on will not stop the outbreak, like you want it to.
Problem is, most of the suppression drugs out there have not been tested for long term effects- they're too new. My gyn is worried because I've been on Famvir for over a year. They don't know what might happen if you take it for a long period of time- I guess that means anything over a year. I had a blood test done recently and am awaiting the results. She just wants to make sure all levels are normal.
Famvir has been a miracle drug for me. I used to have outbreaks constantly. Annoying and painful and inconvenient. I haven't had a single outbreak since I started taking it! I don't know what I'll do if she says I should go off it, I really don't want to.
Whatever you end up taking, ask your doctor about long-term effects, so you know what you may be up against. And good luck.