In a tip from a couple of months ago, I suggested that if you have a method or property that returns a collection, then your method should return only one of three interfaces: IList, IQueryable or ...

But by declaring my return type as class in this way, I restrict my method to only returning that class (in this example, a List). I might eventually want to rewrite the method to return some other ...

You have a method like this that returns a collection of premium Customer objects: Public Function GetPremiumCustomers() As List(of Customer) Dim db As New dbContextObject Return From c In ...