Depends which country you are travelling to and how many visits (one off policy or annual). Is it just you or family? Whether you have any pre existing illnesses, whether you're going to the USA, whether you already have good cover with your bank account, what sort of activities you'll be participating in (loads of policies exclude "hazardous activities" that might seem quite tame when on holiday. Do you already hold a EHIC for Europe? Do you want or need separate dental insurance?
https://www.nhs.uk/using-the-nhs/hea...surance-card/#
https://www.moneysavingexpert.com/in...vel-insurance/
I travel a lot and wouldn't go anywhere without insurance, although touchwood, never had to claim.