But not everyone gets to choose the moment at which they retool for the future. For most, consideration of retooling comes at a moment of professional distress. The hard time may be the right time but rarely feels pleasant.
The marketing guru Seth Godin has identified the growth of "slack time" among both the employed and unemployed as an opportunity to retool. He has two suggestions.
The first is to become an expert in something. Whether it is learning a language, a form of technology or reading an author's complete works, gaining expertise is vital to making yourself valuable.
The next step is to build a following and reputation, perhaps through a blog, a newsletter or offering services to friends and neighbours. "Don't go to conferences, earn the right to speak at them," he says.
One of the greatest quandaries facing people trying to retool and restart in different careers is their lack of experience.
Firms may say they want people with diverse backgrounds but they tend to hire people they can use immediately.
Which is why recruiters such as David Perry, co-author of Guerrilla Marketing for Job Hunters, recommend acquiring tools which can be applied across different professions.
Freshening up your technical skills or adding new ones can be done in the library or on night courses and should be a given. The ability to manage teams of people is critical and what all firms are looking for, he says.
He recommends either obtaining some kind of professional project management designation or getting experience managing teams, through a non-profit, unpaid role if necessary.
The other skills worth acquiring are written and verbal communication. Many people struggle with a properly written letter, he says, let alone a well-structured report. And 99 per cent cannot get up and speak in public.
Retooling is also a time to take stock of yourself, says Perry, and figure out what gets you excited.
Lay-offs are never good, but if you approach them as an opportunity to restart, you should try to think about what kind of work you would do for free.
Once you figure that out, you can think about how much money you might generate.
If you look at yourself as a packageable commodity, he says, you can make a list of the attributes that commodity needs to be attractive to customers, then set about acquiring them.
One mistake he frequently sees is people imagining that their best opportunities lie in adjacent industries.
If they were in finance, they look at careers in insurance. If they were in advertising, they look to public relations.
In almost every case, the people in question keep running into the same problems. What they should be doing is seeking to pitch their talents in an entirely different industry.
By acquiring leadership and communication skills, they will have made themselves much more transferable.
Greg Collett's former colleagues appear to have modified their opinions as the economy has soured.
At first, they called him up out of curiosity, as if watching an animal at the zoo. Now everyone thinks it's cool to do something you want to do, he says.
His own retooling process has ranged from learning an entirely new skill, stand-up comedy, to living with less money.
And, in the process, he has gone from a career path which did not excite him to one which does.
"I was much more concerned about the lack of income when I was working on Wall Street than now," he says.
The people he spends time working with are no longer those in financial services but are the people who might wait on you in restaurants.
The experience has changed his perspective on what is achievable. "Some of my friends are mystified that someone can even do this at all. It's as if I'm building a rocket to the Moon."
Earning any sort of living out of stand-up comedy may take several years, and if he ever finds himself eating cat food, he may reconsider.
But for now he is experiencing something his previous career rarely allowed: fun.
