How long does one brick last?

Scent intensity depends on placement, ventilation, and how often you drive. Gel bricks typically last several weeks before the fragrance noticeably fades. Keep it out of direct sunlight to extend life.

Can I use this with my cabin air filter running?

Yes. The gel releases fragrance steadily, so it works fine whether your climate control is on or off. Just avoid placing it directly in an air vent where it might dry out faster.

Will this stain or damage my dashboard if I set it down?

Gel bricks are stable and won't leak under normal conditions. Test placement on a small, inconspicuous area first if you're worried about contact with leather or sensitive trim, especially in hot weather.