As we move through life, we inevitably close doors that cannot be reopened. But some of these doors aren’t locked; the challenge is recognising which ones we

have a key for.

This is the case with many professional decisions. As our lives and marketplaces change, past career decisions can become obsolete or even dangerous to our wellbeing. This is true even if the decision was carefully made and effective at the time.

However, we should never be trapped by decisions that can be reversed.

The first step is deciding what your second life would look like. With the experience of your first career, you should know what you enjoy and what you could learn to do. But be careful. Even if you want to change careers, you still need to find a field you enjoy.

The reason is straightforward: you'll have less time to be successful in your second career and need to establish your reputation quickly. That won't be possible unless you offer new solutions to key problems. And without a strong interest in the problems that are common in your new job, your chance of offering better ideas is remote.

Unfortunately, those who do speculate about an alternative future in an area of interest often make an immediate mistake. Instead of carefully thinking through possibilities, they quickly dismiss many of them. You need to do your research. If you need additional education, there are programmes that welcome mature students.

For transitions that don’t require a degree or certificate, you can read your way to competence. All the while, you need to look for how you can distinguish yourself and sell that distinction.

And for every obstacle, look for a workaround. It’s important not to get caught up in conventional definitions. Suppose, for example, you want to become an architect, but know that it would take years of graduate work. So instead you become an architectural consultant who advises clients and helps shape the instructions given to architects. In all but name, you are designing buildings. For many people with different aspirations, consultancy is a secure base for second careers.

However, many who carefully explore their options make a different kind of mistake. Because they are starting “late”, they believe they should do a cost-benefit analysis to see if their reorientation is “worth it”. While you should ask this question, approach it correctly. If you only include financial costs and benefits, your analysis is flawed. You need to consider such intangible benefits as personal growth, less stress and opportunities for advancement. – Copyright Harvard Business Review 2016

Larry Smith is an adjunct associate economics professor at the University of Waterloo