On the left is a 17 year old severely corroded starter from a New England vehicle. On the right, a brand new replacement. It looks a little different because the manufacturer has updated the part.
Pictured is the corroded main terminal from the solenoid to the starter motor.
Starters last on average upwards of ten to fifteen years when driven daily. When they go bad it’s random, regardless of low or high miles. Although there are several ways starters can fail, the most common is when the power terminal corrodes and it falls apart due to weather and salt.
So, how do you know when your starter has gone bad? Your vehicle will not start. It’s as simple and as frustrating as that.