We have an 'Availability calendar', where you can add specific days that you are busy, or unavailable. Just select the 'My availability calendar' page from the Sitter menu. Your 'Availability calendar' will then appear in your 'Sitter available' listing when you re-publish it.
Days you are unavailable or busy are marked in pink. Your upcoming assignments are marked in blue.
You can also optionally set your overall availability, via the 'Available from' and 'Available to' fields on the same page. Leave these empty if you want your ‘sitter available’ listing to never expire.