Norcal Approach vs Norcal Departure?

A couple of weeks ago I got to go on a tour of the TRACON facility in Sacramento that we all know as NORCAL. It was a really fascinating tour and very educational. The tour started with a briefing/presentation that lasted almost two hours where we could ask all sorts of questions. The briefing was handled by Victoria, a trainer and a controller. Following the briefing we went into the area where the controllers work and we listened in and watched the controller “work” their planes at one of the stations. I got to sit with a controller directing traffic into Oakland from the Sunol area. It was interesting to see all the various planes in the area as well as you could see the planes at PAO as they were flying around the pattern. I even spotted N35583, a C172SP from SQL, as It was flying into Hayward. One question that was asked is when do you call NORCAL Departure vs. Approach? The short answer is it really doesn’t matter, NORCAL Approach is the best option to use. The official answer is that the only time to use NORCAL "Departure" is on the initial call out of a towered airport when tower tells you to contact NORCAL departure i.e. before you have been radar identified departing from a towered airport.