All kinds of possibilities when it comes to Guard & Reserve. Some are full-time be it AGR (active guard reserve) or a technician (civil servant tied to a military billet; dual hat). Some serve on a tour ranging from a few days to many months, some are deployed. Most are traditional weekend or once/twice per year types. For example, I've been an enlsited IMA reserve (we belong to the RegAF commands) for 20.5 of my 24.5 years but I'm often on some kind of active tour, 3-12 months at a time, and have accumulated nearly 12 more active duty years in addition to my initial entry 4 years RegAF.
Many officers in the Guard/Reserve hold professional careers outside service. For example, a wing vice commander I worked for back in 2001-03 was a retired commercial pilot (think Delta, if memory serves) turned big shot board member, and flew F-16s on his drill days. He later promoted from Col to Brig Gen to Maj Gen and retired. There are many enlisted and officers that are like me - manday whores we're called. Basically, we don't hold full-time work and just find short/long tours and travel the globe supporting this/that mission.