[wvenable]

Your rule of thumb isn't great: If you have some important logic duplicated twice but a year from now has a bug -- are you going to remember to change it both places? But, lets be honest, you probably would not create that code in the first place -- you'd have abstracted it automatically without even thinking about it.

These conversations generally tend to completely discount experience. Junior programs are often terrible at abstractions -- they either do way too much or way too little. Can I give them a hard and fast rule that they can use to never make that mistake? No, I can't. It doesn't exist. The only reason I know what's good or bad is because I've done it wrong thousands of times.

That's the problem with every single one of these articles that prescribe one true solution. It's not at all that simple.