If your bulbs are a cute mass of green foliage, but exhibit little flowers, they need to be divided. Stroll around your garden and stick … hum… a stick next to the ones that need to be separated.
Do nothing but identify overcrowded clumps at this stage. You cannot dig them out until the foliage has completely died back, only then have they withdrawn the energy of the leaves back into the bulbs. It also means that they are dormant and will recover faster from your spade attack in spring time.