Maintaining my British citizenship query (Manila)

Hi Guys,

Quick question, I'm a dual national; British and Filipino, recently my mother informed me that I need to come back to England for at least 2 weeks every year to maintain my citizenship. I am currently working and living in Makati city. I was under the impression that once you're a British citizen it's for life unless you choose to revoke it?

Can anyone shed some light on this please?

Kind regards
Andrew Magno