I agree with sarah and denise - you Know its either the right one or not. Think of it another way - how long does it take you to decide a pair of shoes fits right or not??.......for most people, the first time they wear them!
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"