Be careful with assumptions about how much money you’re going to have in the future. Even if you’re likely going to do well financially, assume it will be less than you think it will be. That way you’ll be including a “margin of error” in your estimation.
There is a mistaken belief, often touted by self-help gurus, that we should make grand assumptions about our future. That mentality also exists in the “prosperity gospel”. It’s the idea that you should not only dream big, but you should already be acting as though it’s a sure thing.
Setting the bar high is generally a good idea, but we should then proceed with prudence, diligence and humility. That way we’ll be less likely to get ourselves entangled in financial obligations that we might not be able to pay.