I think the next bubble will top about $2500 or more, so I won't do anything at $1000. At next bubble top (which I'll try to pinpoint) I'll sell about 10-25% of my holdings.
If bitcoin goes to $1000 better for you to sell rather than burst and drop again to 200. Many investor must sell all his bitcoin when it touch $1000 and then they will buy lower then 1000 again and start to invest again. It wont raise again till $2500 may be in a couple of years after that