In which layer extension methods will come in a 3 tier architecture

Question

I am creating a 3 tier architecture web application, and I want to use extension methods. In which layer should I place the extension methods?

Thanks.

Answer 1

You place extension methods at any layer that uses them.

Extension methods can be extending base UI classes, BLL classes and/or DAL classes.

You place them near where they are used - if they are to be used in several places, you place them in a utility or core class/assembly.