Answer: Keep in mind that many bulbs can be left in place for years so they develop a clump. You would not need to think about lifting and dividing until blooming slows down or you want to start new clumps elsewhere in your garden. When you dig them up, the crowded bulbs usually separate themselves. Then you would replant each one individually.
The best time to dig most bulbs is after the foliage has died back and the bulbs are dormant. You can replant immediately, or store them cool and dry in a single layer in a dark place with good air circulation and then plant in the fall.
Some of the smaller bulbs such as crocus can be moved when they are growing in the spring, dig them with a rootball of soil and replant immediately at the same depth, water thoroughly to settle the soil.
An exception to this would be lilies (Lilium) which are lifted in the fall and replanted immediately, or something like gladiolus which is lifted each fall, separated and sorted by size, then stored cool and dry indoors for the winter and planted outside the next spring.
I hope this helps.
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