If I'm doing anything serious, the apron will usually come out. The primary advantage of an apron, for me, is that it gives you the ability to strap a side towel to your... side. It's also helpful in keeping you clean, but I don't often get food on myself when cooking. Baking or pasta making is another story -- anything with flour demands an apron.
All of this is for "back of house" work. There are a lot of beautiful high-end aprons out there that I find attractive but would never buy because they're impractical to clean. Leather... denim... waxed canvas... gorgeous stuff that you either can't launder or wouldn't want to (denim). Useless materials for the cook. Front of house? Bartenders? Sure. Perhaps if you're a woodworker or a barber or a bladesmith, something like that might be useful. But I'd hate to wear one while cooking.
