Breastfeeding is quite simple and hassle free if you are a stay at home mom.
However, for working moms, in order to breast feed successfully when you go back to work after your maternity, it requires some planning and preparation.
Here are the must haves:

1. Choosing the correct breast pump is very important.
   Many mothers, including myself, buy a breast pump based on recommendation from other mothers, rather than doing a research on what is the most suitable pump.
   I bought a new pump every time I have a new baby, because the previous one was not effective after expressing milk for a few months.
   I only realized when I had my 3rd child that the previous pumps that I bought were not for long term daily use.
   They were just for occasional use.
   When I had my 3rd child, I finally bought a hospital grade breast pump that is specifically meant for working moms to express breast milk a few times a day, every day.
   And I am finally very happy with this pump.
   The kind of breast pump you use really affects breast milk production dramatically.
   
2. I purchased a bottle warmer so that the baby sitter or the nursery can use it to warm up the breast milk conveniently.
    Make sure that the baby sitter or nursery will support breastfeeding, and will not have this attitude that breastfed babies give them too much work.
   Using hot water to heat up the milk is too much work for them, especially when they have to put the frozen milk in the fridge for a few hours to defrost first before they can heat it up.
   
3. The other inconvenience for working breastfeeding mothers is storage containers.
   So far, the types of storage containers that I am aware of in the market are
   1. Milkbottles - this is the most expensive solution.
      I used this solution formost of my children, only to find out later that the BPA from these milkbottles are not good for my children.
      However, BPA free milk bottles areeven more expensive.
      
   2. Storagebags - these are plastic begs that have measurement markings on them.
      Some have sealers that make it quite convenient, but they are moreexpensive, whereas others need to tie with rubber band yourself, which iskind of messy.
      I don't really like to use them because the measurementson the begs are not really very accurate, and I am afraid that I wouldspill the milk easily.
      In addition, it is not very environmentallyfriendly.
      
   3. Milktrays - these are trays similar to ice cube trays for freezing breast milk.
      Each cube is one ounce.
      That means when it is frozen you have small breastmilk sticks of one ounce each.
      The problem with this is that you need totransfer the frozen milk to another plastic beg or container, which meansa lot of handling involved.
      This means the chances of contamination couldbe higher.
      However, it is quite economical, and is convenient andflexible in the sense that you can easily give more or less milkdepending on your child's needs, since you can defrost one ounce at atime.
      
   4. Usedbottles - this is the cheapest solution (almost free), provided you can findso many of these.
      You can use jam jars, vitamin bottles, etc.
      If they areplastic bottles, be sure that they have a recycle code of 2 or 5, if theyare glass, make sure that they are thick enough, and that you do not fillthe milk up too full.
      Otherwise the glass will break when frozen.
      
   5. Plasticcontainers - I have found out that there are actually a lot of cheapplastic containers that can be purchased in the local supermarkets thathas a recycle code of 2 or 5 (which means they are not made from polycarbonate).
      They are not the screw on type, but they are cheap and good.
      As with usedbottles, you can pump into a milk bottle, record the quantity, then pourinto these containers.
      
4. Cooler bag with CO2 ice - this is used to store your breast milk if your work place does not have a fridge, and to transfer your breast milk home.
   You need to store your milk in a cold place to keep bacteria from growing.
   Breast milk can be stored in the fridge for 24 hrs.
   Do not freeze defrost milk.
   

Of course, you need to find a place at work where you can express your breast milk.
You should inform your supervisor and find out about all these before you go on maternity.
Even if they have no nursing room, you can usually find empty meeting rooms, clinics, libraries or pantries to express your breast milk.
If the place is not very well covered, you can always get a nursing blanket to cover over you while expressing breast milk.
Remember to look for a place with a socket if you are using an electric pump.
If you really can't find a place in your office, you can always do it in your car, and use nursing blanket to cover over you.
You can purchase a car adaptor to use your electric breast pump.
To clean your breast pump, you only need water and hot water to disinfect your pumps and bottles.