When I purchase an existing online business, I look for cash flow over the past year and where the money comes from. I want the sources to be more passive so that it does not take a lot of my time. Also, typically I will make an offer that is 18 – 24 months of profit so that I know that I will get my money back within the next two years. I hope that helps!
Most of us think of investment income as just the cash flow we get from bank interest, bonds, share dividends and property rents, some of which comes via a super pension.  But a more complete view is to also consider how growing the value of your investments can add to your spending potential.  This total return approach generates income from both income and growth to optimise spending from your portfolio across all market cycles, aligning cheap and expensive investments to your goals.