For most people, holding 100% of the initial amount is not a wise choice. It is good to diversify by selling into strength to account for the possibility of a black swan event in Bitcoin technology. This way you steadily accumulate also non-BTC assets, and can learn how to handle wealth. You sleep better and don't see dips in price as an opportunity to panic, but rather an opportunity to buy back if you really feel like so. The selling plan must be based on percentages, which means that no matter how high bitcoin goes, you still have more value in your remaining BTC.

If you have BTC1,000 and you absolutely want to have the same number when it hits $million, then it is best to just bury the paper wallet into ground and wake up when you are a billionaire. Trading only makes you lose the most of it over time with no gain. But it is not healthy for anyone to suddenly become a billionaire.

If instead, you flex your Excel muscle and devise a plan to sell BTC900 in decreasing increments at exponentially rising price points, you will already be rich and well-established when bitcoin hits $1 million, and totally content with the idea that your remaining stash is still worth a cool $100M.