The EHIC card may seem like it offers everything you need when you are relocating abroad for any significant amount of time, but not only are such cards only intended to be used by those on short visits to certain countries, but it may also be far harder for individuals to get simple check ups when they need them if they do not know the relevant processes to follow.
When the majority of people think about healthcare abroad, they are considering worst-case scenarios such as serious injuries or diseases. However, sourcing healthcare is also about being able to register with a local doctor so more trivial matters can be dealt with quickly and effectively, and unless you know the relevant process to do this you may find that it is the smaller health problems that cause you the most hassle.
For example, in Spain, you will be expected to get an NIE number or your Residencia Card and a letter from your own doctor in England explaining you no longer intend to seek treatment from them before a GP will even consider adding you to their books. Furthermore, some countries take far longer to arrange such things than others, and unless you start the process before you leave your own country, the infuriating lethargy of the medical systems in certain countries may leave you unable to get healthcare for weeks or even months.
There are of course other alternatives. Expat medical insurance will allow you to miss out many of the hurdles that could otherwise be experienced for both minor and serious medical issues. Furthermore, since such companies will be paying for treatment rather than leaving your treatment being subsidised by a government, you may also find that you are seen far quicker and that you can be seen by far more doctors than you might otherwise be able to.
Furthermore, the right insurance will ensure you are entitled to the same standard of medical care as you would have access to in the UK, and when that is not available you may well be able to be repatriated to ensure you get the treatment you need, when you need it.
With each country being so wildly different in terms of healthcare, knowing what you will be entitled to in a certain country and what you will have to pay for (and indeed how much) might not always be clear, especially when language barriers are placed in your way. By organising expatriate health insurance before you even leave the UK, you will know exactly what you are entitled to and exactly how much your insurance will be costing you before you go, putting your mind at rest and ensuring that you are not left with medical bills you cannot pay or unable to access medical care when you need it most.
As such, it makes sense to get the right insurance before you go and to find out the rules and regulations concerning registering with a doctor in the given country and even in the given area. In turn, if you need to furnish them with letters from your doctor or any other relevant paperwork, you can make sure you have it before you go, rather than trying to source such info when you are thousands of miles away.