The theoretical generalization to more than one period is a multi-period wealth and income constraint. For example, the same person can gain more productive skills or acquire more productive income-earning assets to earn a higher income. In the multi-period case, something might also happen to the economy beyond the control of the individual to reduce (or increase) the flow of income. Changing measured income and its relation to consumption over time might be modeled accordingly, such as in the permanent income hypothesis.
I came across your site and I love it! My husband and I work in corporate America and I own a consulting/coaching business. I have a goal to gross 1 MIL within the next 10 years I’ll be 40 then. How can I begin now? How do I find a millionaire mentor? We live in Philadelphia, PA all of our friends and family are mostly employed some with small businesses however i have huge goals I am working so hard to become a full time entrepreneur. Seems like everyone we know are all on the same level and I fear we’ll stay here of we don’t meet someone willing to show us how to level up. Any suggestions?
The WBG has taken the lead in developing a set of multi-donor programs to reduce transaction costs, aligning support with the country’s decentralized model, and enhancing the predictability of aid. These instruments allow for large-scale leveraging of International Development Association (IDA) support. Such approaches are used in the Enhancing Shared Prosperity through Equitable Services, the Productive Safety Nets Program 4; the Water Supply, Sanitation, and Hygiene Universal Access Program, the Sustainable Land Management Project II, and the Agricultural Growth Program II.

Credit Card Sign-Up Bonuses – This one might not seem like a source of income but ever since I discovered how lucrative churning credit cards can be I consider it part of my income. Just last year alone, I made over $10,000 tax free in travel, cash and gift cards from various sign-ups. It’s not as simple as just signing up for a card though, it requires a lot of research and some maintenance every couple weeks.
I would throw in some caution here: if your spouse works at the same company, or in the same industry as you, you are not diversified, and should something happen, you could be in a world of hurt.  Companies do go out of business, companies do lay employees off.  There is nothing wrong with working together, but realize that you are not diversified and you should be trying to maximize other income streams as a result.
What I’m doing: My realistic goal is to have a blended annual return of 2x the risk free rate. With a current 5% hurdle, I am not paying down mortgages that cost less than 4%. Debt at 5% is a wash. My realistic blue sky scenario is a 3-4X rate of return over the risk free rate which can be achieved with property, stocks so far for the past five years, and certain private equity investments. Where I am dragging is my blended average CD interest rate of roughly 3% from an old CD coming due. I’ve rolled some money into a 12-month CD with CIT Bank at 2.5%. It’s the best rate I can find. 
An obvious example is over exposure to bank stocks, which have been excellent investments for over a century.  Though a foundation of most portfolios, bank stocks do involve more risk at certain stages of the economic cycle than many realise.  Being less exposed to bank shares in the last few months could have preserved some capital.  So, a more diversified approach can help mitigate some of these risks.