I express regularly for DS and have found it particularly useful at the moment as he is off his milk. I can gauge how much he is drinking to prove he is off his food and monitor his intake. Some people can't express a lot or the pump isn't efficient and their bub can actually extract more than the pump so I would just use the expressing as a guide if you decide to do it but you can see how much they are drinking. I agree it will help make more milk if you do it for a minimum of 8 times a day for about 15 - 20 mins per side so it can be a bit of work particularly when you have other kids. I'm not sure if could do the amount of expressing I need to do if I had other children. Occupying one whilst expressing can be hard enough. I tend to feed DS a bottle whilst expressing which helps. There are also some herbs you can take like fenugreek for building supply.