Finding Customized pages

Scenario:
Upgrade is always painful, I was working on one site which has been used from a long time and I wanted to get an idea on to what level pages has been customized pages before I try to upgrade my site definition.

Solution:
Wrote a small utility to go through all the available pages. You can use the vti_hasdefaultcontent field obtained through the Properties property of the SPFile class to determine whether a file is customized.

Code:

SPFile file = SPContext.Current.Web.RootFolder.Files["default.aspx"];
bool IsCustomized = (bool)file.Properties["vti_hasdefaultcontent"];

Article:
MSDN