Engine goes... KNOCK!

If you have metal in your oil filter or at the bottom of your oil pan, the answer is yes. Otherwise the little bearing flakes will cause havoc with your oiling system. It's the only right way to do it and be confident that no "metal monsters" are waiting to eat your engine from the inside out.

I've done half-assed rebuilds on my own stuff (I would never recommend it to a customer) thinking "If i just get one more year", just to find that my oil pressure is steadily dropping and dropping......

I think that the oil milkshake you had just exacerbated an existing problem that was bound to rear it's ugly head sooner or later. Idling it like you were should really not have killed it so quickly. Bust it down.