At first, for a while it may be a good idea to do just one class a week if you are not very used to physical activity, but soon they should become two, which is the ideal frequency for a beginner-intermediate level to gain technique and strength quickly but without too much effort if you are not an athlete. As a new pole dancer, for your first 3 months, you should try to practice or attend a class once a week. For that reason, it's a good idea to leave a week between barbell exercises to allow your body to rest and recover. For example, an inverted shoulder frame or a Superman were considered advanced movements for learning pole dancing.
Before my first pole dancing performance as part of a Halloween show, I practiced every day for the week before. It wasn't serious and it only took me about a day to heal (pole dancing makes my muscles recover a lot), but I had to miss group practice and the last day of practice before the performance itself. When you really start to notice an improvement, for example, when you feel comfortable enough to make an aerial investment, it may be beneficial to start doing some conditioning exercises with sticks on a daily basis. All beginning pole dancers are likely to experience some bruises, muscle aches, and minor frictional burns during pole dancing.
After a few months of weekly pole dancing sessions, you can start increasing your number of hours of practice, if you want. For pole dancing and aerial dancing, it's as important as if you were an athlete training consistently for a long time. Since you're now an advanced-level pole dancer, you should try to make your warm-ups and pole conditioning more challenging. As for how often you should practice when you're at an intermediate level, you can surely practice at least twice a week, with at least one free training session, if you're really trying to improve your pole game.
If you are already physically active, you should also consider your other workouts besides practicing pole dancing, being careful not to overdo it. You should definitely consider another form of strength based exercise, to complement your pole dancing training. Considering that pole dancing is a very intense form of exercise that exercises your muscles in ways that you probably haven't done before, it's common to be careful when it comes to overworking. If you're preparing for a pole competition or a performance, you'll have to follow a very strict schedule to stay on track.
Always take at least one day off a week and remember to always warm up and cool down before and after sessions with sticks to reduce the risk of injury.