on a 2004 grand am i haven't change them ever since i pruchase the car in 2005.How do you know when its time to change your spark plugs or alternator?
Now would be a good time to change out your spark plugs. Every 3 years is rather standard.
Alternator on the other hand, That is one of those things you don't replace it unless its broken! So long as your battery is still charging its still working fine. Your alternator should last at least 10 more years.
