... one other little tip.  I like to buy a little extra on those "blood running in the streets" days.  It has been clearly a winning strategy for me.  Maybe I have just been lucky.  Bitcoin (and poker) has cultivated a fairly high pain tolerance... so "blood in the streets" for me is usually a BAD day, and either close to a bottom, or at least near the base of a good dip, even when more are to come.