Hi, I'm currently building a huge Zope web site, based on two main classes : - a first one, Folder based, which handles the root of the site and many presentation methods - a second one, derived from SimpleItem, which is the base for every object stored into my database (folder based or not) and handles many thinks like security checks, special roles assignation,... My question is : when I have to write a new method common to all my site, is it a better practice to include it in my SimpleItem class, and access it through inheritance, or in my Folder class and access it through inheritance ??? Are there any drawbacks or benefits or using one of these two methods, concerning performances, maintenance, future evolutions...? Many thanks for any help, Thierry