Is there any technical reason to use or not to use var in C# when the type is known?

Question

It seems that more and more C# code I read uses the var type identifier:

foreach (var itemChange in ItemChanges)
{
   //... 
}

Answer 1

var is a C# 3.0 feature only mandatory in anonymous type

Because following code

var v = new { Amount = 108, Message = "Hello" };

dynamically create a new anonymous type, var usage is mandatory. For example, var is particularly useful in Linq where type are often created dynamically.

In any other situations, it's only a matter of taste for final application (it's resolved during compilation). But for code readers, I think 'var' is less informative that type itself.