They don't just invest into Bitcoin and rely on it wholly for the rest of their lives as if they're like real life day traders and that's hard to maintain. As you invest, take it literally to just be an investor and accumulate Bitcoin as much as you can.
Therefore, when the market fluctuates upwards, you'll take the money or profits and when it's the opposite, it won't affect your other source.
That's absolutely correct investment on Bitcoin is good but one must have other source of income as it will be a Big relief to easy some tension in any market fluctuation, also help you to hold for more profit. I love my professional job as it help in getting some daily living QS job . But gor any that is not professional can get involved in job some small enterprises even the POS can help allot in solving daily needs thereby prolonged your investment.