That all depends! Depends on how many miles you're driving. But the older cars - there's ALWAYS something that needs service. They're not known as daily drivers.
Drop into a dealer and just have a frank discussion about this with them. These aren't your Ford and Chevy dealers - the sales guys are pretty sharp... and they're car guys! Go have a good old fashioned face to face with them and voice your concern. They'll be very honest with you.
These are like big ol' fish killer boats.... Like 70 foot Bertrams and Hatteras etc... They're running Twin 12 and 16 cylinder high strung diesels - they burn 90 gallons per hour - and an Ad for one always has the "SMOH"...... SINCE MAJOR OVERHAUL... 'cause an in frame overhaul is measured in the 10's of thousands...

But these boats cost 2 or 3 or 4 and 5 million... 50 grand is nothing. Fueling a 1000 gallons of diesel for a weekend of fishing or going to Bimini is something you don't even think about. Have another bottle of Cristal!