I expressed in the early days to maintain supply as ds had latching issues that took a few weeks to resolve. I continued to pump on and off but it reached a point where BF became easier and the lazier option. since then, I've put put the pump away and haven't used it for ages. I BF ds and when I have had something to drink or dh is doing a feed, we just use formula. ds has on average 1-2 bottles of formula a day, the rest are all BF (especially at night haha, I'm too lazy to get out of bed when it's freezing lol).
my ds is 4.5m and we are at the point where BF is just the easiest option.
you definitely don't need to pump.
what do you do if you're going out/having a few drinks? just give formula instead?