in my opinion i do the way if bitcoin fall down i convert immediately btc/usd pair i keep usd in my exchange  when stable the price at low point i can rebuy the bitcoin with usd  i keep btc ,  so i can gain at least some $ for that. another way i do is i sell out btc for cash instant in local bitcoin exchange or other exchanges i keep cash when btc stable i buy back with cash if anyone selling because a lot of panic sellers will sell at any point of time in exchange i can enter that time to buy back .
but if price is not constant then i will buy some alt coins  which are green in market or updates or announcement or fork news  i keep it untill steady the bitcoin then i convert back my alts to bitcoin, i take some little profit for holding alt coins also.