Hi julie, that is a great question
The truth is many people in more mature years take out private medical insurance.
The healthcare system is free on the old E111 forms for UK residents, but as you are probably not UK resident you are not entitled to this.
Where are you resident? France?

The simpliest but most costly offer but greatest peace of mind is private medical insurance.

The situation for people living and paying taxes in Spain you are entitled to medical treatment from day one. Personally I have used the hospitals, they are ok to good. I would advise to speak to people in the medical field, or healthcare and insurance fields.