NEW YORK (MainStreet) -- For Americans looking to add some much-needed income to their retirement savings once they leave the workforce, boundaries - geographical and otherwise - arent all that necessary.

Take Carol Merchasin, an author and former law firm partner with Morgan, Lewis and Bochius in Philadelphia, whos now living with her husband in San Miguel de Allende, Mexico.

My husband and I boosted our retirement income by leveraging what we did before we retired into less stressful and more part time employment that doesnt require being in an office or even in a particular place, Merchasin says. When I left my law firm, I continued doing training but only as an independent contractor, often doing webcasts from Mexico. Now, ten years later, at almost 70 years old, I still do webcasts and I develop and audit training programs. All from wherever I want to be.

Merchasin also published a book of essays on Mexico called This is Mexico: Tales of Culture and Other Complications and does speaking engagements on Mexican culture from a US expatriate perspective. Her husband, also a lawyer, invested in a small property with three apartments that he now rents out to short term visitors to San Miguel. Our long term strategy has been to support ourselves without touching our nest egg until we were 70, but we are still keeping with that strategy for a few more years, she says. Boosting retirement income for us has meant not taking anything out and allowing it to grow as long as were still able to work comfortably at our own pace.

Financial experts say that Merchasin is on to something, and that, since Americans may not be saving enough for retirement, they should seek extra income while theyre in retirement. Living comfortably in retirement isnt so much about how much money you have, but more importantly what counts is having a solid cash flow plan in place that includes a very clear income and distribution strategy, says Gary Plessl, a certified financial planner who co-authored The Book on Retirement (Richter Publishing, 2015). 

The data support their notion that many Americans just wont have enough cash saved up for their after-work years, and will need other avenues toward income once they retire from their full-time careers. Millions of Americans are in danger of not having enough money to maintain their standard of living in retirement, states the Center for American Progress in a new report The Reality of the Retirement Crisis. The problem is getting worse over time.

As of 2013, the median retirement account balance among all households ages 55 to 64 was only $14,500, the CAP reports, and almost one-third of Americans in the workforce havent saved anything for retirement.

If youre in the same leaky boat, and are wondering how you can earn extra income in retirement, Plessl and Houser offer a few key tips to follow.