To be fair, almost nobody is going from childhood vaccinations > late-middle age without seeing a doctor. And when you do go with an ailment general blood tests seem pretty standard these days at GP's along with standard vitals checks. They also do preventive care where necessary. Every woman is invited for cervical screening once they turn 25 and then every few years until they're in their 60's. Regular mammograms are also a thing after a certain age/depending on risk factors. Bowel cancer screening too. STI testing is free and, depending on where you live, done by post. Also depending on your definition of 'childhood' there are a few vaccines given when you're a teenager (HPV for example). And if you ever travel you'll be visiting the doctor for vaccines then too.