Although you may expect your fireplace to get dirty with extended use, it’s not intended to be this way. The fireplace should be kept clean, even if soot seems to collect quickly at the bottom of the fireplace. And if this is the case, you should do whatever you can to ensure this is kept under control.
Part of this is regular fireplace sweeping. Part of this is prevention. But you should also be sure to call in professional technicians to clean your chimney and fireplace at least once per year, and help you make changes to reduce soot and debris buildup in the first place.