The best time to buy Bitcoin (and any other coin/token that has a solid project) is when it receives corrections from my point of view. Then we will buy cheaper, but not only will we have it at a better price, but we will also be avoiding possible losses in the short term. This is one of the main "strategies" I use and it has worked quite well for me so far. Buying when the price is going up is insane, and don't worry, there will always be price corrections.