prepend category in SEO-friendly URL

I have a website that contains "items", that have an ID and title. They are divided into categories.

Category indexed are viewed at URL's like

example.com/tutorials
example.com/maps

What would be the best URL structure for the items themselves, from a SEO point of view and just semantically in general.

example.com/tutorials/12/Make+a+php+site
example.com/maps/29/Inside+the+moon

or

example.com/12/Make+a+php+site
example.com/29/Inside+the+moon

The category addition in the former is actual unneccessary. I only need the ID to find an item. However, I somehow feel the latter is better.

What do you think?

From stackoverflow

• The categories are very important SEO-relevant keywords, it would be better to have them in the URL, even if they are not needed.

• I agree with PeterP - just having /12/Make+a+php+site doesn't give any context to the reader or search engine. Also, IMHO, plus symbols are ugly. Use dashes instead (like SO) :-).

• I would use the most descriptive URL, without appending unnecessary information. If these are distinct categories in your website, available through separate menu items, I would use the

  http://www.example.com/Maps/12/Map-of-the-world

  form.

  If 'map' or 'tutorial' are more like tags or classes that are not unique, or can be multiple per item, or have no separate landing page or menu item, I'm not so sure. Best to include the most basic relevant information, and from your example I would suggest including the category.