Replacing water heater due to age........

Ok, was at the beach last week and one of my friends suggested I should change out my Atwood 6-gal. water heater since it is 17 years old. It's working just fine, but, he feels it could be deteriorating on the inside and could start leaking/flooding the RV. Seems replacement is $375-$475 so not a lot of cost. Obviously, anything can wear out and start leaking, but, wondering if anyone has done this simply due to the age of the unit?