The best opportunity to invest on a cryptocurrency is when it is just starting that is why people are still investing on ICOs because it is cheap and has the potential to grow more depending on the project, but the thing is not all ICOs have that potential that is why when the project's token becomes available in an exchange the price becomes cheaper because investors are dumping it because they really don't believe on it, they just want an easy money and it becomes a routine that investors will immediately sell their tokens because it is expected that most investors will do the same, and they are afraid that the price will drop and their investments will be stuck.