Is it good or bad practice to make stateless methods static?

Visual Studio Code Analysis and ReSharper suggest to make those methods static, because there is a tiny performance advantage:

From documentation:

Members that do not access instance data or call instance methods can be marked as static (Shared in Visual Basic). After you mark the methods as static, the compiler will emit nonvirtual call sites to these members. Emitting nonvirtual call sites will prevent a check at runtime for each call that makes sure that the current object pointer is non-null. This can achieve a measurable performance gain for performance-sensitive code. In some cases, the failure to access the current object instance represents a correctness issue.

For non "performance-sensitive" code this is a matter of taste. I personally obey to ReSharper's suggestions if I have no good reason to not do so.