Travel insurance

If anybody knows any information about travel insurance.
Is it different from a country to other or depends on the country that i will go?
is it mandatory in all counries because i travelled many times but without insurance ?
need some details please
Thank you

It depends on the country that u will go

It not mandatory for all the countries as they haven't asked for it when you applied for the Visa. but it's better to have travel insurance just in case of any accidents.
about the prices it depends on its coverage, duration and the country you're traveling to.

if they asked when i should do it ?
thank you

When you apply for any embassy to get entering visa they ask for some papers like ticket, Travel insurance, bank statement ,,,etc