The UK NHS invite women over 50 for a mammogram without expressly recommending it, setting out the balance of risk and benefit (
https://www.nhs.uk/conditions/breast-ca ... s-offered/) which is pretty blanaced according to the Chochrane review (
https://www.cochrane.org/CD001877/BREAS ... ammography). Shingles rarely strikes twice so the vaccine seems a bit marginal, as does colorectal screening (
https://www.ncbi.nlm.nih.gov/pubmed/27133893). Flu vaccines in healthy adults? Cochrane finds minor reduction in flu, and relatively minor side-effects (
https://www.cochrane.org/CD001269/ARI_v ... thy-adults).
Dr McDougall is far more forthright in recommending us to steer clear of avoidable treatment than I can be without medical qualificaitons. He recommends some vaccines (not for flu) and does not recommend colonoscopy or (as I recall) breast cancer screening.
When I saw a cardiologist who mentioned possible treatment, I did not want to seem rude so I asked him, rather than trying to tell him, whether the evidence pointed to better outcomes in case of intervention. He said, 'it is a good question; it depends.' So if I were offered colorectal screening I would probably ask the doctor about its benefits for all cause mortality (answer: probably none), as well as for reducing cancer risk, and listen carefully to whether the doctor presented familiarity with the evidence and compelling arguments, or evasion.
Personally I would also not want the blood tests. If they find high blood pressure, or high cholesterol, or sugars, they might prescribe medication whose benefits are unclear at best. Famously, in the Helsinki Businessmens Study, the group who saw doctors (who did recommend healthy diet) had lower cardio-vascular disease but higher death rate than the untreated group. So you can take your pick of which risk you prefer to reduce: cardio-vascular disease or death. The following brief journalistic summary repays reading:
https://www.sciencedaily.com/releases/2 ... 085917.htm. Its conclusion is much the same as the reply of the cardiologist (mentioned above): intervention might make sense for high-risk cases.