Having an emergency fund that is 3-6 months worth of expenses is also good, and planning cashflow in advance, and surely a person who has a 6 month cash reserve is going to be able to be much more aggressive in his BTC investment approach as compared with someone who has 3 months or less of cash reserves.
If an investor has an emergency funds, that will also help the investor to hold for a long term and also help him or her to accumulate more Bitcoins without getting to think about whether to sell a little of his or her coins to sort out some personal issues at hand.
One of the things some investors do is to try to see if they can accumulate up to a whole BTC or more, but the interesting part of it is that they can not achieve that if they don't work hard to achieve it.
And some might end up half way and some might not reach even half because there might not be a steady cash flow or over-expense might be the cause of it.
Still, they can never achieve upto 1 BTC if they don't have a steady cash flow just like you already said, but even with steady cash flows, if they don't try as much as they can (like holding their guns and not looking back but always ready to fire more money into their investment,,, they can never achieve a whole BTC).
So, the best way to achieve a whole BTC or the little one they can get is just to stick to their plans and never get tired of accumulating it.