When to stop breastfeeding?

I am set that I am not going to breastfeed very long. Some is better than nothing right? I am thinking a month or so... This will be the time that I dedicate to my daughter almost 24/7 but eventually I want to go back to work some and I don't want to pump. I'm completely fine with formula feeding and I didn't breastfeed my first born at all. This time I tried it and it's gone fairly well but I am not doing it for super long.

I'm just wondering if there is a certain time that would be best or how to go about doing it? Do I wean her off for a while? Will that make it even worse on my boobs if I cut down but don't stop? Will it be way more painful since I've built up such a supply?