I'm (nearly) 30, and the biggest change I've noticed is that my skin has gotten progressively less oily for the past 2 years or so. Whereas I used to always identify as oily skinned, it is now definitely combination, trending towards dry in the winter. Doesn't bother me, though--hydrating layers are easy to add and much less annoying than all of the mattifying products I used to use. My acne as a teen wasn't terrible, but what acne I do get has vastly improved in the last couple of years--not sure how much of that is due to age and how much is due to an IUD, but I'll take it either way. I used to get occasional breakouts on my jawline (probably from shaving irritation thanks to PCOS), but since I started double cleansing and shaving with my oil cleanser I rarely get those anymore. Other than that, I notice my skin isn't as 'bright' as it used to be and some fine lines at the corner of my eyes. The biggest sign of ageing I've experienced is my hair--I started going grey at 19, and now have a distinct thick streak of white (like Rogue or Cruella de Vil) running through the front of my hair. I like it, though, I think it gives me character.