This is the main problem because no one knows when will be the right time to buy alts. Because sometimes it is not on the price weather it is high or low sometimes we also need to consider the kinds of altcoins that we buy, there are a lot of high price altcoin that can still make a 3x profit and there are also very low price altcoin that can still make us loss. We buy the dip? It is less risk but still no assurance because we cannot control the price I think the best way to earn is to select the proper altcoin to buy even price is high.
When it comes to buying it is good to always keep in mind that the best thing is to know how to choose the altcoin, in my case I do not choose an altcoin that comes from a nascent project, this is something that is also buying to try your luck and I would not be thinking with reason In the case of BTC it is different because BTC is a safe currency, in case it goes down, I have the full conviction that the price will rise at any moment, or even if I have to wait some time I know that will happen, I would not risk with altcoins new, for now I would go with altcoins that have a lot of community and a relevant future.
For me, i still go with the basic buy at the dip and sell when its peak. With bitcoin and altcoins, for me it still works. But there is higher risk when it comes to altcoins particularly for new projects as they tend to have high potentials to have higher value at first, but when the market suddenly dumps, unfortunately most of them did not recover again. So if you want to be more secured when you invest, go with the old and prominent projects as they have sustain their position for a long time, and if the market suddenly makes a correction, they never fall so deep as they can recover easily from any type of dumps. That's the advantage if you stick to old, yet strong projects.