 <p>No, it is not a good practice for large applications, especially not if your static variables are mutable, as they are then effectively global variables, a code smell which Object Oriented Programming was supposed to "solve".</p> <p>At the very least start by grouping your methods into smaller classes with associated functionality - the Util name indicates nothing about the purpose of your methods and smells of an incoherent class in itself.</p> <p>Second, you should always consider if a method is better implemented as a (non-static) method on the same object where the data that is passed as argument(s) to the method lives.</p> <p>Finally, if your application is quite large and/or complex, you can consider solutions such as an Inversion of Control container, which can reduce the dependency on global state. However, ASP.Net webforms is notoriously hard to integrate into such an environment, as the framework is very tightly coupled in itself.</p>