US long term capital gains taxes are between 0 and 20% [1].
The popular definition of a bear market starts at 20%; if you are really bearish, you might "expect the S&P 500 to lose about two-thirds of its value over the completion of the current market cycle" [2].
Either way, giving up 20% of your gains beats losing between 20% and 66% of your entire holdings (initial investment + gains).
Regarding derivatives, they are (1) not free, (2) of limited duration [3] and (3) only as good as the counterparty [4]. They can make sense if you have good reasons to expect a short blip. The longer and deeper you think the downturn will be, the less useful they become.
