Another working mom here. I've only used a medela pump in style advanced that we bought when J was a baby, & it has seen me thru 2 kiddos, pumping multiple times a day for ~10 mo each time. So that's a lot of pumping sessions on my pump! I've never had problems with it. Emma says you can get it serviced when it starts to get "tired" (internal parts will wear eventually), but I haven't even had to do that yet. I'll probably do it if #3 comes along.
You can get replacement tubing, valves, different sized flanges, etc (things you can see) on line or at places like Babies R Us. If you go the double pump electric (as you probably should, working), call any lactation consultants in your area. My LC offered this pump at a significantly cheaper price than Babies R Us, & the BRU was the last year's model!