If you ever get a flat tire on the road, you'll want to know what kind of spare tire your car has. That way, if there's a tire emergency and you have to go looking for your spare tire, you won't be caught off-guard when you don't see it.
Temporary Fix, A donut spare tire is for temporary and limited use only. It is a lightweight spare that is manufactured with smaller physical sizes (when compared to full-sized tires). Additionally, these tires require higher psi levels. The spare tire air pressure is much higher, as a donut spare tire needs around 60 psi to properly function. These tires do not offer the same traction and performance matching full-sized tires provide. They should be changed as soon as possible. The advantage is that you save space in your car for storage.
It is a Great Idea that you may consider having these handy accessories in your trunk.