Their is always going to be a risk associated to investing. It doesn't matter if you are investing in future commodities, precious medals, stocks, currency or bonds there is always going to be some kind of risk. Timing a market is always going to be something that you have to do no matter what you are investing in. For Bitcoins if you invested say last year and you are comfortable with your gains that you have received so far I would definitely cash in right now. Yes the price could go higher but it can also go much much much lower than what you originally invested for. The biggest mistake most investors make is always waiting on an investment to turn it around when it starts to fall. It may turn it around but you might be looking at 10-15 years in the future for an investment to turn itself around to get back to the value you once had. Basically what you need to do is set a point at where you will be happy with your return on investment. So say you invested in Amazon lets say 5-years ago at about $250 for 1-share of stock in Amazon. Now today Amazon is selling at about $1150 per share. At any point that an investment grows to where you are happy with the return you should be selling or at least putting a stop limit order in. Lets say you put in a stop limit order today for Amazon at $1000 and that is where you are comfortable in taking your gains from this purchase. This will allow to keep the stock but if it does fall you can limit your losses. Now Bitcoin you can't really do this as there is no stop limit order you can put in. You have to watch the market carefully and plan carefully for it. If you got into something like Bitcoin and you already have gains that you are comfortable with you should definitely be looking at the risk factors and then determining if you should sell or not. If you are comfortable with taking on the risk of your investment disappearing then keep on holding onto those Bitcoins but if you are not comfortable with the risk definitely cash out now.