Are you talking about your serpentine belt (the one that is visible from under the hood)?
If it hasn't been changed before, then yes I would suggest you do it. Not a difficult job. Check the tensioner and idler to see if they need to be changed, too.
If you're talking about timing, then you don't have a belt, as MM notes you have a timing chain. Absent noise it can pretty much be ignored.
If you can tell that your starter is going, then my suggestion would be to change it. Personally I'd look for a rebuilding shop around you and have it rebuilt, that should be cheaper than a rebuilt starter.
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