Spring bulbs are generally left in the gorund all year. If they are dug up, it's to move them. Some gardeners will dig up their tulips this time of year and replant in September or October. Gardeners who irrigate their gardens (or live in wet summer climates) tend to have better success with their tulips by doing this. If you dig now and don't replant until next year, you're not meeting the seasonal requirements of spring bulbs and they will rapidly decline.
Many are from desert climates (as are tulips) or others with dry summers and may benefit from being dug and stored during summer, to be replanted in fall. Others will tolerate this treatment to a certain extent but would prefer to be left in the ground. Ideal handling depends on specific type.
