I totally agree with you that cryptocurrency investing takes years to make a profit, but it totally depends on the currency you buy. If it's a scam or a bad project, you should sell it as soon as possible. Many investors are overly optimistic, buying tokens from ICOs and holding them until they disappear from exchanges, and project websites are closed.
because of that, time can answer, however, if it's a quality project, then it's worth the wait. whereas if there is a lot of potential scams in it, you should immediately stay away from projects like that, because the future can be seen from the laziness of the team running the project. however, it all takes time to look at.