We're supposed to wait until the foliage turns brown on spent bulbs to remove it. The bulb is storing energy for the next year while the leaves are turning brown. But sometimes after flowering, the leaves start to lay down, look messy and/or cover up other plants. Some say it's ok to cut off the leaves after the blooms have gone. I've read and heard both ways. I believe it's good to wait.
Just thought I'd share what I did at a job this morning. I like to braid the leaves as it makes the area look nicer. This was a huge clump of Paperwhite Narcissus, must be 40-60 bulbs. The leaves were laying on the Daylily behind(below in my photo). I didn't have a lot of time, so I braided a couple clumps and knotted the rest. If you've never seen this done, it might look weird. But it neatens things up and makes it easier to remove the leaves when they finally do turn brown.