OT: Heading levels in a UG

[Evanth, Henrik]

Hi All

I have an off-topic question that may or may not interest you. 

We are having a discussion at the office regarding the maximum levels of heading that a User guide/User manual can/should contain. Do you know of any best practice rules that define how deep a publication should/could be. Personally I think that 6 levels is too deep for a user, but that is just a personal preference that I cannot back up with "evidence".

Heading 1
   Heading 2
      Heading 3
         Heading 4
            Heading 5
               Heading 6
   
Insights, comments or instructions are highly appreciated.

Best Regards
/Henrik