Hi and welcome. The answer will vary person to person to exactly what they can achieve without irritation. From the reading I have done some don't do all the passes as it will cause irritation. Personally to start with yes I would have irritation and get little pimples on my neck if I did too much on my neck to start with and still do if I chase bbs too hard. I can do more now than when I started as my technique is far better. Try for close comfortable shaves and in time you will find your shaves improve without trying as your technique gets better. At about 100 shaves is where things have really come together so you have a ways to go yet and even then they will continue to get better. As you mentioned burn I would say lighten up on pressure and lower the angle. They are the 2 most common starting out mistakes. Good luck