Why are only 2 months visible when others read my calendar ?
Outlook defaults to 2 months of Free/Busy time viewing. You can set this default up to 12 months manually to allow others to view your free/busy times 12 months in advanced. Follow the steps below to change the default.
Click on Tools and select Options
Next click on the Calendar Options button to display your calendar default settings.
In the Calendar Options window click on the Free/Busy Options... button.
Change the Publish contents from 2 to 12 and click OK.
The free/busy times on your calendar are now available to others scheduling items for you for up to 12 months.