Different uncertain circumstances can hinder one from having numerous source of income but if one is in a better situation whereby they're fit or healthy enough to have numerous source of income then the better for such folks cause more source of income means more discretionary for investment and more funds to take care of other expenses too and more discretionary means a higher rate of accumulation to yield more profits, that's why when an investor has held for so many years, many about a decade or so it would be wise for the person to take some profits and create another source of income, maybe a business that would generate more income and discretionary to accumulate more Bitcoin and add value to their portfolio.
Earning money from multiple places is great idea if you are healthy enough to do so. More income means more money for you to invest and cover your expenses. This helps you build your wealth faster. If investor has held asset for a very long time like ten years it can be smart choice to sell portion of it. They can then use that money to start new business. This new business can become another source of income providing even more funds to invest and grow their portfolio.
Yeah you are very correct however if you have hold your Bitcoin for ten years and you are now ready to start selling them in other to start up another business it is good you sell only 5 to 10% each time the price of Bitcoin doubles so any business you want to go into should be in the range of the profit you will get when you sell 5 to 10% each time the price doubles now the reason why you should maintain this rate is because you are not sure of how the business you are going into will turn out so you need to make sure your Bitcoin investment is still very much intact for you.
Some people make the mistake of selling all there Bitcoin just because they want to start a new business or investment with the money and after selling it and the start there new business or investment some time later it crashes and they lose it and also lose their bitcoin investment so keep your Bitcoin investment going while trying out other business or investment.