The point at which you should have your serpentine belt changed depends on the vehicle. It is best to check the owner's manual. That said, under the best of conditions, the belt should last from 60,000 to 100,000 miles, depending on the vehicle. This doesn't mean the belt won't need to be adjusted at some point before it needs to be changed.
That would be a judgment call on what the old belt looked like.
Your belt should be checked for cracks or tears if you see these it should be replaced asap
Only as needed. The serpentine belts hold up well unless there is a problem with the belt tensioner or any of the driven accessories.
never
You firts pull out the battery, and then you slip out the starter cables, and right where the belts are you snap those and that's where the serpentine belt should be changed.
in answer to your question the timing belt should be changed every 55/60 thousand miles
Possibly the wrong belt was installed or most likely your belt tensioner is bad.
There should be a belt diagram under the hood.
According to my dealer, it should be changed at 150,000 km.
Most serpentine belts can be changed on the side of the road. It is usually an extremely simple procedure.
If it has a serpentine belt it should have an automatic belt tensioner If it doesn't have a serpentine belt then alternator should be the adjustment/pivot point
check to be sure the routing of belt is correct