For eggs it does matter - just 30 seconds extra cooking changes the texture of the yolk. It's actually hard to get the perfect yolk, you need very exact timing,

For eggs it does matter - just 30 seconds extra cooking changes the texture of the yolk. It's actually hard to get the perfect yolk, you need very exact timing, most people seriously overcook eggs because they'd rather that than raw. The yolk is supposed to be set, but just barely, and not dry. This is especially true for egg salad where the softer white and creamer yolk dramatically improve the flavor. If you Google you'll find plenty of photos of yolks at various stages of cooking so you can see what I mean.