What should I use Sleep or Timer

Question

I have two alternative using timer or using sleep, I need to call a method every 3 seconds after this method is finished, I wrote basic example to demonstrate what I mean:

Answer 1

Do you realize that fooUsingSleep is calling itself over and over? It will eventually generate a stack overflow.

If you are using timer, it can be as simple as this:

    System.Windows.Forms.Timer t = new System.Windows.Forms.Timer();
    t.Interval = 3000;
    t.Tick += new EventHandler((o,ea) => Console.WriteLine("foo"));