If you could buy insurance coverage after an accident, you would. When we lose a job, we can start work on our resume, but it feels better to have the insurance already in place.
A resume is a part of a personal job insurance package. It is not the only solution, but you have to do it and having it ready provides a feeling of having a safety net.
In these tough times, it makes sense to take some precautions. Get your resume prepared. If you never need it, you may find that it helps you appreciate how much you have accomplished in your career, and possibly give you the explanation you have been seeking to ask for a raise one of these days.