Right after a major stock market selloff is probably the last time you want to submit to a financial health checkup. But if you're planning on retiring at any point, it's a smart move.

Where you are on your retirement timeline could alter the prescription post-selloff, though. The course of action for those just starting out their careers and retirement saving plans is far different from that of investors hoping to retire within a handful of years.

When You're Young

This age group has it pretty simple: one of the best moves is to simply do nothing.

After a market crash has taken place, there's no way to turn back time and make it go away. Selling just after a market crash, or as the market is tanking, is a fear-driven response and typically one of the least strategically savvy.

If it's a short-term selloff, dumping out of the market could mean you miss out on the rebound. And if you have a whole savings career ahead of you, you'll likely end up buying back in at a higher price.

After all, the stock market just about unequivocally moves higher over time. Even recessions don't last forever. If you're in your 20s or 30s, take pause, assess the damage, buckle down and wait it out. The market tides will turn back in your favor eventually and names like Apple (AAPL) - Get Report and Boeing (BA) - Get Report will rise again.

When You're Near the Middle

Those closing in on the middle of a career might have to be a bit more proactive. Consider the names in your retirement funds that perform the best in the darkest times. Following a market crash, what holding was left standing highest?

If one of the names in your 401(K) didn't do as well in the bull market and then fell harder than the rest in a selloff, it might be time to consider pivoting out of that holding into one that did better. Hindsight may be 20/20, but it can serve as a useful gauge for what's strong and what isn't. 

Also consider the risk to which you're exposed. If your portfolio looks riskier than you thought it was after you weather a selloff, it could be appropriate to consider a passive index fund -- one of the most predictable investments and a favorite of billionaire Warren Buffett.

When You're Ready to Retire

This is the toughest spot to be in during a market selloff as far as retirement is concerned, but it by no means spells disaster.

One of the best means of winning back lost ground just before you retire is to find a way to boost your income going into savings. Consider cutting back frivolous spending to invest more aggressively in the market. Investors who can buy low might be able to capitalize on quicker short-term gains just after a market crash.

It's also important to pile in at least enough at this time in your career to ensure your employer will match your 401(K) contribution, provided the company offers such a program. If you aren't contributing the minimum to reach that match, you're essentially throwing away free money.