Certainly, a C-Type visitor can stay up to 180 per visit. And more than 180 days per year if a visitor is making more than one trip in a year to the UK. However, most of the visitors have an active life in their home country. Therefore, usually, the stay is no longer than 2-3 weeks for business visitors and tourists. Even most of the family visitors usually don't stay longer than 1-2 months per year.