It depends on the person; with meds like Paxil, it is sometimes trial and error before you find the right one. I have been on Zoloft in the past and went back on it after a year or so. Both times, it was for about a year even though I felt/feel great. Most docs want you to stay on it for that time. It sounds like it worked before and that you tolerated it well, which is a good thing in my opinion. Keep us posted!
I was on Paxil for 3 years and went off it to have my first child. I think it stopped working for me. I went on it after having the baby and I just had to keep increasing my dosage. Finally I am on Celexa and feel normal. Aside from panic attacks, of course, which I do still have.
Just talk to your doctor about how you feel on the medicine and go from there.