Many CBD products will come with it's own dosage guide, but some may not. Although there are charts to determine how much you should take, your body chemistry could make it that you require a lot, or very little.
Figuring out your dosage is a bit of a trial and error situation. Always follow a dosage chart and start with the lowest recommended amount for your weight. Slowly incorporate more if you feel like the dosage you are taking is not enough.
Your body doesn't build a tolerance to CBD the way it does to regular marijuana. That means when you find the right dose for you, that's all you'll ever need.
Here's a dosage chart that I've used that I found helpful:
If you're ever left wondering what dosage you should take, a general rule of thumb is 1mg-6mg per 10 pounds of body weight.
So if you're 200lbs, you'll need 20mg for low dosage, about 50mg for medium dosage and 120mg for a higher dosage.
At the end of the day, everybody is going to have different dosage levels. It's just going to require a bit of experimenting. Just remember to start low and gradually increase as needed.