Due to the fact that that we are still in beta and the markets are also quite volatile I would say to keep your steempower untouched unless you want to trade your steem now. I have never powered down since last year that I joined and only powered up. I tried to power down the other day just to see the process. You can do the same. You just have to wait a week. 10% of your steempower will be converted into Steem. You can power up right after if you want.