Adeline,
All my 3 kids are like that, only drink one side. So each breast's interval is 5 - 6 hours.
As I've mentioned before, during 1st month, it's best not to express as there are lots of colostrum in your milk (ie the yellowish fluid). Expressing too early will deprive your bb of the colostrum.
If you do not feel engorged/fullness, there is basically NO NEED to express. However, if you feel uncomfortable, you may pump to relieve the fullness.
I didn't take any alcohol during my confinement except for #1, only managed to finish 1/2 bottle of Martel. With #2 and #3, totally alcohol-less.
abc,
As above, I'll prefer not to express in the first month. You may start expressing 2 weeks before you return to work.
When I was still working, I was using the Ameda. With abundant supply, I only pump for 10 - 20 mins and can achieve 3 - 4 letdowns. That's when I was nursing #2. With #1, it was tougher as my supply wasn't much to start with, I need to express for min 20 mins to get 2 letdowns. I was using Medela single and NUK single (works as a dual pump for me).
Kell,
If you want to breastfeed, keep your pump and bottles away.