Whatever investment that you are doing that doesn't guarantee you a specified amount of profitability in the end is a risk, and Bitcoin is not excluded from that. Mind you whatever you hear people say about bitcoin getting to certain price level in the future are mare speculations. There is no guarantee that it will play out that way. Also relying on past performances of bitcoin as a proof of future performance is also risk of it's own. So when you have invested in bitcoin and your plan is to hold it for 5 years, that's risk on it's own because you are not guaranteed of making profit. That's why the risk in long term hold is not zero. You can't take speculations for facts!! If you had known the specific amount of profit you will make at the end of the 5 years before investing, then you can say there is zero risk. But since there is nothing like that, there are still elements of risk involved, because it may happen the way you expects or it may not. And it is advisable not to be over reliant on your bitcoin investment so that you don't get into trouble, when your projected time of holding comes and things don't go the way you planned. That you hold bitcoin for 5 years does not guarantee you profitability. That's the risk in it.
Everything that is Investment especially Bitcoin has a fluctuating nature where the movement of the graph is not measured accurately, from here everyone can speculate about the future value, those who do have their assets certainly think this will be much better in the next period and this we estimate is reasonable, and actually this does have risks and all Investors admit it.
However, it seems that targeting the Investment time too much does not sound effective to do, considering that this is a volatile Bitcoin making speculation that can later be seen with the profits obtained with each change, maybe we say when it moves down it is better to hold or continue buying and but when the graph is to the increase number you can collaborate your choice to continue to survive or return a little profit first.
You sound lost here because firstly it's not all investments that fluctuates so if you were to be more specific it would have been better and yes people do use charts to make speculation of future market prices but it is not a guarantee that those speculations are going to be accurate.
Talking about targeting investments time I assume you are referring to market prices so if that's what you mean then it's true that after making investments it is not necessary to monitor the market fluctuations anymore as those who does that are mere traders and not real investors so after making investments our targets should be on how to grow our portfolio instead of targeting the market all the time then if the price fallls it is an advantage to buy at a DIP price and hodl instead of buying at a DIP and expect the price to skyrocket and then you take little profits, it is a bad investment mentality.