That is a great question. I tell patients that the end result depends upon the amount of skin aging, and your satisfaction with the level of improvement. Often, one treatment is enough to provide significant improvement. In some cases, a second pass over troublesome areas is necessary. In general, CO2 laser resurfacing provides the best results.
This is a great question. The answer depends on a variety of factors. What are you trying to change? (Color spots, texture, pore size, wrinkles etc. Your skin type also plays a significant role in expected results from laser. There are many, many different non-ablative lasers, and each of these has many, many different settings. The more aggressive settings will give you lasting results in less treatments (maybe even only requiring a single treatment). The less aggressive settings will have a quicker downtime, but will require repeat treatments and may never be able to get you the same final result as a stronger laser treatment.In general, there are two camps for laser treatment. There are those who use gentle, less effective lasers and settings. These treatments offer quicker recovery, but the results from each treatment are less powerful. This requires you to spend more time and money getting additional treatments. Each treatment has a quicker recovery, but cumulatively the recovery days (and $) can add up.The other method is to do a more aggressive single treatment, with the understanding that you will get a more powerful result right away but you will need more time for recovery up front. Even if you prefer the stronger laser treatments, your skin type may not allow for it. Good luck and warm regards.
Typically, with a non-ablative laser, you will need multiple sessions to see a difference. However, it is imperative to have a physical assessment to reveal the true answer to this question. This will depend on what your skin concern is, which laser is being used, and what your end goal or expectations are. It is also possible that a non-ablative laser is not the best option for you based on those three points. Best of luck on your research and I hope you get results!