CLOS extends the Common Lisp philosophy of emphasizing developer flexibility, possibly at the expense of execution efficiency (not trying to open a can of worms

CLOS extends the Common Lisp philosophy of emphasizing developer flexibility, possibly at the expense of execution efficiency (not trying to open a can of worms here). For any application of substantial size, I can't imagine not using CLOS classes and generic dispatch. It may be overkill for small projects, but as the code complexity grows the abstractions of CLOS make their worth known. That's been my experience most recently with my 3D graphics system.