Although there's no hard rule for when you can stop wearing a nursing bra, there is a guideline for when you should wait before switching back into your pre-pregnancy bras. Most guidelines center around when to reintroduce underwire bras to your routine, with the La Leche League recommending to wait at least a few months. But you may find that you'll want to keep wearing nursing bras until you stop breastfeeding.
Your breast size can fluctuate even for seasoned nursing parents. This means that just before feeding, your breasts might be a cup size larger. You'll want a bra that can comfortably accommodate that without pressing against your breasts or digging into your sides. Additionally, most standard bras aren't made with drop cups — meaning that you might find the process of adjusting your regular bra tedious when it is time to nurse.