Has this ever happened to you? You start out with a simple project — to update a faucet fixture — and invariably end up replacing the trap and a whole slew of other pipes beneath the sink. What should be a 45-minute project snowballs into a whole day thing, with multiple trips to the hardware store for parts. Here's where conventional "advice" you get from sales assistants in the plumbing aisle is just *plumb* wrong and what I'll do differently next time I touch a kitchen sink.