If you had the power to lock in the price on the turn of the year to 2019, what's the lowest price you would be willing to accept. Some caveats, you can't buy more bitcoin or bet on the price etc, it's purely based on your current holding.

Personally I would take a price of $10k right now, anything lower than that and I think I would gamble. This is mostly based on my own circumstances and what that value would mean to me financially.