No one that we have met who lives in Great Britain has told us they like the NHS. The waits are so long for virtually everything that people suffer unimaginably from mundane ailments that would be treated immediately here. And as you say... if you have a life threatening ailment that needs immediate treatment especially if you are old... you better just start making arrangements for the benefit of your survivors. That is something we know from our friend who came to visit us.
In a system like that, I’d simply schedule an appointment every 4 months whether sick or not.