Hi, so I thought I’d pass this information on from my vet in case this would help anybody. While seeing a vet for yearly visits even if everything seems okay is still ideal, there are reasons why we may not be able to do that, so what he recommended is to weigh your turtle regularly if you can’t see a vet for yearly checkups. Often before a turtle shows any other signs of health issues, the first sign is their weight starts to steadily decrease, so buying a small scale (like the type they have for kitchens) can be a way to monitor your turtles health yourself. He said while they do perform other checks during the yearly appointment, this is the most important one and the biggest flag something may be wrong, so especially if you own a few turtles, getting that scale is a good investment.
Info courtesy of Dr. Lou at CMVH