Frequency of Shoulder Exercises

Well, I continue to be sidelined with sinus issues (going to the doc again tomorrow) so I've made a resolve to at least do some core work, basic strength exercises (think squats and lunges) and shoulder stabilization exercises while I'm out of the pool. However, I have no idea how often I should do these, particularly the shoulder exercises? So... Those of you that do shoulder strengthening exercises: How often do you do these? Daily? Every other day? Less? Any favorite exercises? I do the rotator cuff ones both with (very light) weights lying on my side and also standing up using stretch cords attached to a door knob. I do some other stuff with the stretch cords too. Thanks for any info!