I bought a Yamaha P-

I bought a Yamaha P-200 keyboard and love it. I don't play gigs much anymore, mostly since I've been living out of the country, but not yet somewhere I could take my piano. I've started thinking about whether I should give my Yamaha P-200 a new, more appreciative home. I don't want to get rid of it. I'm just worried about whether it would lose it's tune or otherwise depreciate in it's usefulness. Question: I remember the salesman telling me this board could go out of tune if not played regularly. Is that true? If so, how quick could it happen? And what would it take to re-tune it again? I have a Kimball piano in my parents' house waiting for me to have a permanent home to take it. I don't foresee being able to take it soon and don't want my parents to have to move it again. So we talked about getting rid of the Kimball. Our thought is that the Yamaha P-200 really feels and sounds so great that I could handle keeping it instead of the upright acoustic piano (I can't believe I really believe that-- I am NOT an electric piano fan, but I do love this one)! I'm just worried about what will happen to the Yamaha P-200 while it sits mostly unused for a year at a time. It has sat most of the past two years and is fine, but what about the future? Does anyone have any insight-- I would really appreciate it. I believe in loving instruments and taking care of them!