There are three kinds of wrinkles, and each has different causes and needs to be treated differently:
Dynamic Wrinkles
These wrinkles are caused by repeated muscle contractions. The facial expressions that we repeat most commonly create these lines. The most common are frown lines, crow's feet, smokers lines, the horizontal lines on the forehead, and laughter lines. That's the kind of lines that get Botoxed.
Static Wrinkles
These wrinkles are caused by the loss of skin elasticity (break up of skin collagen) due to age, sun damage, environment, nutritional problems, etc. These wrinkles look like cross-hatch or very fine lines in places like the cheeks or forehead. They are called 'static' because they are visible even on poker-faces. You can't Botox these lines, and their appearance make the face look tired (dynamic wrinkles without static wrinkles make you look freshly old
Wrinkle Folds
These are more folds and grooves than wrinkles, and are caused by "sagging of the underlying facial structures", which in plain English means that your facial muscles are limp. A typical wrinkle fold is the groove between the nose and the mouth.
Coming up: a detailed view about each kind of wrinkles, how to prevent or treat them. I feel a bit of a humbug, writing about wrinkles at the age of 26, but I've stumbled on a couple of interesting things which I think are worth sharing.