I will describe some recent work on applying Effective Field Theory (EFT) methodology to three different physically interesting systems. First I will explain the philosophy and general methodology of EFT. I will then present three short vignettes. The first has to do with the application of EFT ideas to the Standard Model of particle physics. The second will show how EFT can be used to understand the behavior of quantum fields in an inflationary background. And in the third, I will show how EFT ideas can be applied to a numerical technique for quantum field theory known as Hamiltonian truncation.
