Accordions let users click on content to reveal additional content associated with that item.
In a nutshell, if you’re uncertain, don’t use them. Basically, you’re always safe not using an accordion. However, there are various traps in using them.
Here’s a list of Pros and Cons about them and where you should and shouldn’t use them.
Pros:
- creates a mini table of contents
Cons:
- you have to click on each heading to access more content
When to use them:
- when the sub items of your content are exclusive – e.g. someone will only want to click on one item. An example, being a list of conferences
When not to use them:
- when the user may want to open the majority of the items
- if the user may want to copy and paste the entire content
If you do decide to use one, a key rule is – do not auto close them. If a user wants to copy multiple items of content you’ve just created a major usability problem.
See also: http://www.nngroup.com/articles/accordions-complex-content/
and http://ux.stackexchange.com/questions/23181/when-is-it-bad-practice-to-use-an-accordion-control