I decided to stop breast feeding and express after 2 months because I just couldn't keep going with it.
I worried about supply dwindling and thought it was probably the beginning of the end but that hasn't proved to be the case. DD is now 4 months old and we're still going with it.
I now do 5 feeds a day - the first one a breast feed, 2 of expressed breast milk and 2 of formula.
I express between 3 and 5 times a day. Don't think it would be sustainable to try and express all 5 feeds but for a month I was managing to express enough for 3 EBM feeds.
It is a bit of a faff but still a massive improvement on exclusively breast feeding, which for me was a nightmare. As soon as I made the change, everything improved. Before feeding had been fraught and anxious, but with EBM I know how much she's getting and we immediately fell into much more of a routine.
I now enjoy the morning breast feed, and if I'm caught out and about without any formula or EBM, I do an extra breast feed with none of the bad side effects that I suffered when exclusively breast feeding.
I'd say go for and see how it feels. You can always go back to breast feeding if you decide you want to after a bit of a break.
Oh, and my massive GG norks are a bit more manageable now that I'm expressing. Whenever I do more than 1 BF a day for a few days, they balloon again!
Good luck!