Around 15 to 16 migraines per month are normal to experience.
However if you experience more than 16 migraines per month and the migraines come and go every month for a few months then the migraines could be a sign of something more serious such as cancer.
However not all migraines are caused by cancer or are a sign of a brain tumor but if you are experiencing a lot of migraines then you should go to urgent care, see your doctor or if serious enough get to the emergency room.
If the migraines get worse or last longer than a few days or you have a migraine every day of the week for a week or longer then something is likely wrong and you should get checked out.
There are some months where I can experience a migraine every 3 days or so and they get worse but so far they are nothing serious.
Stress, anxiety, high blood pressure etc can all cause migraines.
Also if you're a woman on your period then you can also get headaches related to that.