Will this spill if my car gets hot or bumpy?

No. The glass pendant is sealed, so the fragrance won't leak even in heat or rough driving. Just keep it hanging level from your mirror.

How long does the scent last?

A 110G fill typically lasts several weeks depending on heat and how much your vehicle is driven. When the scent fades, you can replace the pendant or refill it if available separately.

Can I adjust how strong the fragrance smells inside the car?

The scent strength is consistent once hanging. If you want less fragrance, remove it during hot days when volatilization peaks, or hang it slightly away from direct AC vents.