As part of Yahoo Finance’s Investing 101: 5 Rules to Build Wealth special, Decoding Retirement podcast host Robert Powell joins Brad Smith to discuss the third rule: building your retirement nest egg with actionable tips and how to do so through every career stage.

Young professionals early in their careers should prioritize paying down their debt, "whether it's student debt or your credit card debt, especially your credit card debt," Powell says. The next thing is to “consider investing in your human capital,” a worker’s experiences and skills which “represents the largest asset that you have about 90% relative to maybe 10% of your financial capital.”

Finally, Powell recommends young professionals contribute "to your 401(k) enough to get your full employer match” and think about investing aggressively as young people “have a long-term time horizon” so “you could afford to invest 90% of your assets in equities.”

For those in the mid-career stage, Powell says the focus shifts to resource allocation as “you're balancing different goals” while “trying to save for retirement at the same time.” At this stage, some may be weighing saving for their children's college education against saving for retirement, but Powell underlines “you can't borrow for retirement” but “you can borrow for college.”

Another factor is to maximize saving toward retirement is to “think about trying to hit the 15% mark” for savings. Powell also says mid-career professionals should create an investment policy statement to get a sense of your investment timeline and goals as well as your risk tolerance and then rebalance accordingly.

Retirement is “a case of being rows and columns” where “each year you need to be looking at your expenses and adjusting them accordingly, and then making sure that you have sufficient income to match those expenses,” Powell says. If retirees find a shortfall between their income and expenses, part-time work could help close the gap.

Another concern for retirees is “outliving their assets in retirement” or “the risk of longevity,” which could lead some to consider investing in an income annuity, which is something that will pay you an income for the rest of your life.” Once in retirement, you “need to think carefully about your asset allocation, just as you did when you were mid-career, but now maybe you need to be a little bit more conservative with your investments,” Powell says.

Powell tells the Wealth! team that the “general rule of thumb is that you should aim to replace 70% to 80% of your income in retirement that you had prior to retirement,” though this can vary in different income quintiles.