This topic has been touched upon in some threads but further discussion is needed, methinks.

Case in point: My wife is a commissioned salesperson. Her year-to-year annual income can vary by tens of thousands. Indeed, she just landed a million-dollar order with a 5% commission (that's on top of her already 7-figure sales). Should I bump up her annual income by 50 grand now?

What counts as income? Is it last year's income? Is it last 12 months' income? Is it this year's expected/estimated income? Does only earned income count? How about unearned? If one plans to pull money out of, say, an IRA this year, does that count? What if one ends up not pulling it out? Or pulls out substantially less than planned? What if a new grad (with very little income) has accepted a lucrative job offer; is that as-yet-unrealized salary what should be reported? Or who cares because Chase is never gonna verify income* anyway?

*Yes, I know business card applications can get scrutiny, but that's another can of worms.