I've been on the thyroid medication for about 2 1/2 months. It's amazing the difference it has made. My symptoms became noticeable to me in March, and with 20/20 hindsight I could trace it back another year or so. However, I've noticed improvements in things that could probably be traced back at least five or ten years, perhaps longer, and which I had no idea had any relationship to my thyroid. I won't bore you with all the things that have improved, and it would be verging on TMI, but I'll give you the highlights. I've got a lot fewer aches and pains, my balance is better (it was getting worse, which I attributed to bad knees from soccer and being out of shape) and it's a lot easier to drag my lazy ass out of bed in the morning.
Things just creeped up on me, and I assumed that it was just because I was getting older, or could attribute my symptoms to other, completely logical causes. Rest assured, I'm still a cranky old biddy, though.
PS When I first posted this, I forgot to mention the best change of all. My shoulder is healing up and feels a lot better now.