Agreed on the point that you need to look at the entry point in the currency invested, tempting to use the dollar value, but useless if Bitcoin is outpacing your investment. Works going down too, can still increase your Bitcoin holdings even when the dollar value is dropping. Stop loss is a useful tool, just remember to adjust it upwards if the coin value is increasing. It's all very well to say 'Take your profits at their all time high', but not much use when most are trading well below it at the moment. I tend to look for big short term increases (20%+) and take a profit there, there is normally a hefty adjustment after a sharp increase which will enable you to get back in if you want to.