This is a question that is frequently asked by IT support technicians, and it generates strong opinions on both sides of the argument. Usually those discussions in online forums generate more heat than light, with a lot of “mine is bigger than yours” and “you’re just lazy” themes.
To save you the suspense of reading to the end, I will give you the definitive answer to this question right now. It is never in your best interest, and rarely in the client’s best interest, for you to wipe and reload the system. Clear enough?