Some of us are wired to be "Researchers." Whatever the decision (a car, nursery school, internist, or vacation plans), Researchers are compelled to analyze every aspect and angle. Each purchase is viewed as an investment worthy of considerable time and effort to insure that they make the right choice. Consumer reports, on-line reviews, interviews, and input from peers are sought out prior to any decision being made.
Others of us are wired as "Satisfiers." While also concerned with making the right decision, satisfiers spend less time on research and have a greater trust for their instincts. They will do basic, but not extensive research.
Although studies have shown that Researchers usually makes the 'better' decision because of all of their efforts, they are less content than Satisfiers. This is because they constantly second-guess themselves and wonder if there was information they missed that would have altered their decision and outcome.
I am not sure one can change their natural disposition. As a Satisfier, I am fortunate that my closest friends are Researchers. I am completely comfortable following many of the decisions they have made, knowing that they have been extensively researched and thought through. For me, that is the best of both worlds!