Diversification can save your capital. I think every investor should use this strategy. This is a very important time when the market is falling.
If you can handle going broke you can also go all in on one thing, but it's not really a sound strategy.

I think that many users of cryptocurrency went all in at the end of 2017, when in order to invest profitably in cryptocurrency they sold real estate and took loans. This misstep brought them some losses.