The most common signs of a bad serpentine belt are cracks and other wear on the belt or even squealing noises coming from the engine bay especially when you accelerate.
If the belt is squealing then it's usually a sign that the belt is stretching and is about to break eventually and then leave you stranded.
Your vehicles serpentine belt powers your power steering, water pump, air conditioner and alternator.
So when your serpentine belt breaks and goes bad then you will lose your power steering, water pump cooling, and your alternators ability to keep your battery charged.
A serpentine belt that breaks will leave you stranded and if it breaks you need to call a tow truck to come tow your vehicle.
A serpentine belt on a vehicle should be changed every 100,000 to 150,000 miles or every 5 or 10 years depending on how much driving you do.
Serpentine belts will get old overtime and the rubber will break down and it will begin to crack so inspect the serpentine belt for cracks or possible stretching.
I usually only need to change the serpentine belt on my vehicles every 5 to 10 years or after 100,000 miles or more and I will always replace a serpentine belt on my vehicle if it's been longer than 5 years and I plan to go on a long road trip.
I hate being broken down and when a serpentine belt goes bad and breaks then you lose the power steering, water pump cooling etc.
So your engine can be damaged as a result of the serpentine belt breaking and also you'll be stranded unless someone is near to help you.
It can also be a good idea to buy a spare serpentine belt and have it with you on a long road trip or just when driving around and have the tools to change the serpentine belt.
The hardest part about changing a serpentine belt is finding out how it routes around the pulleys as sometimes that can be challenging.