If you bought the puts between 440-450 there were multiple opportunities after that where the stock was lower. Even a month ago, it was close to 440 again

- I am not so sure about "multiple opportunities". Looking at a 1y chart I see one perfect opportunity: End of July/beginning of August the stock was down to below 430. Had I not been so stubbornly convinced the price would retreat to roughly my strike prices of around 400 then, yes, I definitely should have then sold them. That was my big mistake!

- Otherwise I see only 2 big spikes down to around 450, plus 1 month ago to around 440. In all 3 cases thanks to the decreased time value those long ago bought puts were already near worthless (-80% or more), so I decided to just hang on and wait for a miracle (as just happened when I sold on Friday with only a tiny loss 1/2 of my BABA calls which until just one month ago were hopelessly under water).

You can use the same strategy as you described earlier, but instead of buying puts when you think the price is high, you sell calls.

I would never sell naked calls or puts. For that I am not gambler enough. Without an for me unacceptable high risk only buying calls or puts give me the very high leverage I want when I think Berkshire is at the lower/upper range of it's valuation.

(I am fully aware that I am an options amateur. So if what I think about theoretically unlimited (selling calls) respectively nearly unlimited/extremely high (selling puts) risk is wrong (without using complex option strategies), please correct me.)