Will this gel spill or leak while I'm driving?

No. The gel construction is solid, so it won't slosh around or spill like liquid fresheners do. Road vibration won't create a mess on your dash or seats.

How long does each gel freshener last?

Lifespan depends on cabin temperature and how often you use your vehicle. Gel formulas typically fade gradually over weeks; when one scent weakens, switch to the other one in the pack.

Can I use both scents at the same time or should I pick one?

You can run both simultaneously if you want a blended scent, or rotate them—use one until it fades, then switch to the other. It's your call based on how strong you want the fragrance.