I only apply this rule to trading, not investing. I have almost myoney in bitcoin and I convert to stable coins sometimes and back to bitcoin. Is this risky? I think it is worth going for than holding fiat.

But the rules applies to altcoins because some at just shitcoins and a good one just like how Luna was before it become a shitcoin, we can say altcoins is like you are gambling so should've treated that one. There is still nothing bad to invest 10% of my bitcoin on altcoins, outof 10% taken, some should be profitable, but this will be after a significant bear market which I am still expecting.