Does a ten-year visa mean ten years in the UK?
No. A long-term Standard Visitor visa may be valid for two, five or ten years, while each visit is normally limited to six months. Special provisions for particular purposes are separate questions, not a general permission to extend every trip.
What does visa validity mean?
It describes the period during which the visa may be used, subject to the conditions attached to it. A multi-year visa does not authorise one uninterrupted stay for that whole period.
Why does your wider travel pattern matter?
Visitor permission is for temporary visits. Repeated trips should not be used to make the UK your main home. A simple count of days cannot explain every situation or replace consideration of the overall circumstances.