As of now, under Administration » Custom fields allow only one field Type "Selection combo" to have the "Edit options..." button.  The "Edit options" goes to a page that has the "Make this field dependent" button.

Use example:

If a user makes a selection in one field/question (text box, checkbox, date, address, number), this new feature could allow them to then see a series of fields/questions appear.  But only after they start answering the preceding question (as in, the parent field is no longer empty).  

If the parent field is not empty, then show the specified other custom field(s).  Or if it's a checkbox that is checked, then show specific additional custom fields.

Benefits:  

This would help reduce the fields visible on the screen for those of us that have been required to have a large number of custom fields.  And more importantly, improve the user experience by guiding them through the ticket and not letting them fill in fields without filling in others first.

A: Screenshot from custom field, "Selection combo"

B: Screenshot of options that appear when the "Edit options" button is clicked.

C: Screenshot of options that appear when the "Make this field dependent" button is clicked.