What to do wih tulips/daffodils once flowers are finished

(Question)

 What should I do with my bulbs and daffodils once they have finished flowering.  Should they be cut them down to base or let them wither to the ground?

(Answer)

 Let them die back (wither to the ground) ,  Cutting them down to base would restrict the flow of end of season goodness from the leaves back down to the bulb so plant can store essential substances underground.  Foliage replenishes energy that has been lost through flowering.