For my first pregnancy, I continued to express breast milk at work till my son was 8months old. I had enough inventory to last him till he was 13mths.
Does your workplace have a nursing room and fridge? I think to be able to express breast milk at work, you need to have an understanding boss and a conducive environment for pumping. Coz you will need time in between work when you have to be excused to do 'mummy duties', and you need to feel comfortable to have your milk let-down faster. For me, I invested in a double pump after I started work (coz the single pump that I bought initially took me 45mins to finish pumping both sides, wash up and all) The double pump shortened my pumping sessions to 15-20mins!
For storage, I bought a dedicated deep freezer to store all my ebm. Each packet of breast milk is dated and consumed from oldest stock first. I used nanny milk storage bags that I purchased from food for totz. Everyday at work, I freeze the ebm immediately after expressing, in my office pantry's fridge (I keep the filled ebm bags in a plastic container in an opaque plastic bag to be discrete) Then after work I bring home in a cooler bag with reusable ice blocks (bought from Daiso at $2 each!) and continue to deep freeze.
And if you need to pump several times at work, some time-efficiency tips include:
* Buy 1-2 spare sets of pump parts (funnel, membranes etc) so you dont't have to wash up after each time. Just use a clean set for each session, then bring home to wash and sterilise at the end of the day)
* Put the full set of pump parts (without dismantling) in a clean and sealed tupperware container and freeze/fridge the whole thing immediately after each pumping session. Take out to reuse directly for the next pumping session. (I didn't try this method myself coz I prefer to use clean pump parts everytime, it was an idea from another mummy friend of mine)
I continued to latch my son at night when I am with him, to bond with him and also to continue stimulating my supply. There are lots of things to carry to and from work everyday...but to be able to give my son breast milk was rewarding and definitely worth it! He only tasted his first formula milk in his 8th month, and was totally weaned off breast milk in his 13th month. I thought that was the most satisfying thing for me as a first time mummy.
Hope my sharing helps! All the best in your breastfeeding...!