Could be the change in season which leads to changes in humidity, esp. if you crank the heat in the winter.

Also, again, check your action, you may want to live with slightly raised action versus messing with the frets.

Finally, you should check the truss rod setting, not something most techie-type guys would recommend you set up on your own, but I have adjusted the truss rod (in ignorance) on my acoustic and electric, and they both have beautifully low action now. Check to see if the humidity change was affected your neck's curve. I've adjusted mine to be basically straight, but I'm sure someone here (read: Lordathestrings) will correct me and tell me that the neck should be slightly curved or something.

That's all I can think of.