What I usually do if prices are falling most specially if the coins are very low, I would buy more coins from a much lower price and your total amount of couns would then be divided; the result would be lesser losses. Read or research on google about books or ebooks on trading.
This. Dollar cost averaging ftw.
The DCA is good metodhe to buy bitcoin, we can use our capital maximally by using this methode. But how about lump sum? Since bitcoin prices keep rising it will be good to use lump sum methode, we only need to know the lowest price of bitcoin that might be reach.