This is a very important aspect in trading. Holding a crypto coin will let us participate from any future price increase, while losses in the meantime will only be realised if we actually sell our coins. That is why HODL investing is so attractive and profitable for many investors. Timing is the most important thing for day traders, only when they sell above their purchase price they are making profits. For day trading technical analysis is important and can predict trends to find the best timing to buy and sell. But when it comes to general trends there is a lot of politics involved. One good or bad news by a big government or investor can change the market. It's better not to try and find the lowest possible price, because if we wait too long we could miss out on the next rally. Once bitcoins reach a new ATH it doesn't matter so much if we bought our coins at 25, 30 or 35,000 USD.