总的说法是任何1年内离境不超过180天，不过看那个详细的PDF指南似乎即使周末或是年假出境Holiday也要雇主开证明，能有经验的帮忙确认下么？
原文：
Absences linked to reason for being in the UK – evidential requirements
For all other categories, absences must be consistent with or connected to the applicant’s
sponsored or permitted employment, or the permitted economic activity being carried out in
the UK, for example, business trips or short secondments.
This also includes any paid annual leave which must be assessed on a case by case basis
and should be in line with UK annual leave entitlement for settled workers. For example,
the statutory leave entitlement is 5.6 weeks’ paid holiday each year, which for workers who
work a 5 day week is 28 days’ paid leave. However, many employers provide 25 or 30 days’
paid leave a year, plus bank holidays.
Short visits outside the UK on weekends or other non-working days are consistent with the
basis of stay and do not break the continuity of leave. You must count such absences
towards the 180 day limit.
Evidence in the form of a letter from the employer which sets out the reasons for the
absences, including annual leave, must be provided. Where short visits outside the UK, on
weekends or other non-working days have taken place, evidence from the employer should
be provided to confirm the applicant’s normal working pattern and show the absences
occurred during a non-working period. Tier 1 (General) applicants who are self-employed or
in business must provide a letter of explanation of their business-related absences.