for altcoins i suggest buying them when you see price not going lower any more and if you saw signs of a rise. and then dump them as fast as possible to get out again because the continuation of dump is highly possible for them.
for bitcoin i suggest buying when the dumping slows down, because for bitcoin the price can easily be reversed and it happens fast, you can't really find a bottom for it. and additionally it doesn't matter at what price you buy bitcoin, you will make profit in long term.
Dumping is slowing down now and holding. Did anyone able to buy back when the price dip? I hope so.
I guess the weaker hands have folded. Last time I checked the price its $2200 so indeed, it is now holding good to know. If you guys where able to buy at $1800-$1900, I think you can made a good profits by now. But just continue to hold because another wave of buying will come so the price definitely go up again. For altcoins, you need to be always alert and ready to dump, because when the dumping started, you don't want to be caught napping because for sure you will loss your investment.