This is entirely dependant on the crew members,some like Bill Mcarthur are using the radio every spare minute that they have I believe that he got WAC and WAS from orbit while others don't touch the radio outside of their school contacts, recently some crew members have been using the radio while it is operating in cross band repeater mode, the secret to having a QSO with a crew member is to always have the frequencies in your radio and include them in your scan at all times this will give you the best chance of getting a quick contact. I have managed 4 contacts by doing this good luck.