This is important especially at this point in the market because we are so low already with the prices of cryptocurrencies however the old saying is if we go down 80 nothing is stopping us from going down another 80 so we want to identify the best times to be buying altcoins for those longer-term swing trades
The best time is always when the market is at its bottom and from looking at how the market has been trading for sometime now, we can all agree we're at the bottom or closed to the bottom. This means you should start buying now and keep some funds Incase the market was to dip further. You shouldn't buy all your coins ones as the market always present an opportunity to get coins at cheap price. Bitcoin was trading a $67k and no one believes it can even go below $20k but it did and so did other altcoins as well.
If you had fomo all in when it was at all time high, you'll be regretting now but assuming you kept some funds after buying then, you can easily make up for that lost as you get your hands on cheaper coins and wait for the market to return bullish for you to get your profit. The crypto market is all about patience both when you want to buy or sell.