I used to have facials every few months over the past 10 years or so, but have only been having them about three times a year lately - I've had three different aestheticians (sp?) and they all did extractions, but mainly because I needed them. Just as Janeen explained, when they look at your skin under that super-duper magnifier they have, they see things we cannot see with the naked eye - so if you need extractions for blackheads, or because your pores are "congested", they usually extract. It's slight trauma to the skin, so I don't think they do it unless necessary.
They feel great, don't they? I did hate the extraction part, but it was usually short-lived...I finally asked my aesthetician to show me how to do them properly, which she did, and I have done them on my own from then on. But facials at a salon are a necessary iindulgence!!