Yeah for sure there's an art to it that only comes with experience. But you better be 100% sure you need those three layers. My first big project as a developer

Yeah for sure there's an art to it that only comes with experience. But you better be 100% sure you need those three layers. My first big project as a developer was on an over-designed reporting/query-builder application that had like 7 layers of of abstraction between the browser and the database - stuff like just in case we ever want to switch from Oracle to Sybase, unnecessary connection factories, Java controller classes for every type of html form field, etc (still have no idea why we needed a back-end CheckboxController). I ended up maintaining that thing and it was a great lesson in premature optimization. The bottom 3 or 4 layers remained a grey box that I did everything to avoid touching. Just changing the front-end query-builder flow from a series of forms to a flat panel that could do everything in one step involved ripping out half the back-end code. All those layers of abstraction and none of them considered a form-flow change, which is exactly why I never assume anything now. It's so much easier to add a layer than remove an unneeded one, which can be practically impossible on a complex app.