Hashoff can keep a calendar up to date with your approved leave and the public holidays you observe. You subscribe once. New leave shows up on its own, and cancelled leave drops off.
Do not forward it. Anyone with the link can see your leave. Pending requests are not included — only leave that has been approved.
Pressing Add to Google Calendar in Hashoff opens that From URL screen for you. Google can take a few hours before a new day of leave shows up.
On an iPhone, the same Apple Calendar button opens the subscribe sheet in the Calendar app.
Outlook on the web is the reliable way to add it. The desktop app sometimes refuses a feed that the web app accepts. Updates can take up to a day.