There is a natural yellowing from coffee, tea, smoking and aging that even disciplined hygeine doesn't combat. Whitening (via oxidation) is nothing like surgery, being a meager, inexpensive, 5x5 minute habit that has a pretty big impact on perceived health and grooming. The downside is some temporary damage to your enamel, but it's less than a single cleaning at the dentist. If anything, I'm wary of whitening toothpastes, which are ubiquitous and tend to work via abrasion.