I've been pumping once a day, just to build up a babysitter supply (for evenings out, etc).
At the moment I have a medela swing (one sided). If it's plugged in (not on batteries) I can easily get 3oz from each breast in 5 minutes (if I pump in the morning). So I've been filling one 6oz bottle and stopping. The other day he slept so well at night that I was quite full come morning and got 6 oz from only one breast so I only pumped that one.
Since I'm doing this for extra milk rather than to build or maintain my supply, does that matter? Or should I be pumping each breast for longer or until the milk stops?