Spaying and neutering your pets has been recommended for years...just ask Bob Barker. But where and how you go about having this procedure performed *does* make a difference.
Shelter and low cost spay/neuter clinics exist for a reason - we have overpopulation of stray animals, and preventing reproduction goes a long way to reducing those numbers. Most shelters will not even adopt out their animals without first having these surgeries. And shelter and low cost surgery is a bit how you would imagine it - the pets are anesthetized (often with only injectable medications), surgery is performed and they're sent on their way. Often 50 or more patients are having surgery done that day, so things move along at a good clip. What these vets and organizations are doing cannot be undersold - they are providing a great service for those who need them, and I really don't want to disparage them at all. But they are working with some serious volume, limited resources and limited staff. So let's look at the other side of the coin for a minute.
At a high quality veterinary practice there are a few more steps. Your pet receives their examination and has pre-operative blood work run to look for any reason that anesthesia would be inadvisable. Then an intravenous catheter is placed to provide immediate venous access in case of emergency, as well as to provide intravenous fluids for the losses sustained during surgery. Pre-medications that include pain management are given, as well as a separate induction agent to make your pet sleepy enough to be intubated. Intubation allows for use of inhalent gas anesthesia without risk to the veterinary staff, and allows for better control of how much inhalent is actually being delivered to your pet. During surgery your pet is monitored by a trained individual whose job is dedicated to monitoring your pet's ECG and blood pressure, their level of anesthesia and comfort. After surgery, that same individual stays with your pet until they are awake enough to have the endotracheal tube removed safely. Heat support is provided during and after surgery. Your pet receives additional pain medication while in the hospital, as well as some to go home. An elizabethan collar (cone) is also sent home to prevent self-trauma to the surgery site.
There are veterinary hospitals that are somewhere in between these two. They may not place a catheter in every patient, or they may not intubate. ECG and blood pressure monitoring might be optional, pre-operative blood work may not be done. There are levels and levels of what is going to happen when you drop your pet off for their procedure. And the cost differences that are out there will reflect those levels. I don't want to tell anyone that can't afford to spay or neuter their pet at the high end of this spectrum that they shouldn't do it - that is why low cost options exist, and I'd much rather have the surgery done, period, as it significantly decreases certain health risks later in life. But I do want people to understand the fundamental differences in what these surgeries entail, to ask the right questions to compare them, and to be aware that a spay is NOT just a spay.