What are the big no-no's that break content type inheritance to a site?

Question

In my organization I have experienced that suddenly the inheritance have been unintentionally broken to a site, so that new lists or subsites only have local - obsolete versions of the content types. It seams to happen once in a while, and the consultants have no idea who did what wrong. Does anyone have a list over actions that can break the inheritance for content types, so that I can distribute the knowledge.

Answer 1

There are two posts that may be useful (with good caveats) regarding Content Types & Inheritance:

• Rob Windsor's Custom Content Types and Inherits in SharePoint 2010
• Serge Luca's SharePoint 2010-Content Types and Inherits : the good, the bad and no ugly