As stated, no harm in seeing if another lender can give you a lower rate without a bunch of closing fees.
If that doesn't work, you can also save interest costs by increasing your monthly payment. Every little bit you add helps lower your principal balance which lowers your interest amount. Just make sure your lender applies any extra payment towards the principal. The lender on my motorhome purchase was taking my extra amount and applying it to the next payment. When I contacted them, they corrected the situation and adjusted my previous payment accordingly i.e. as payments towards principal.