Which holidays usually cause a shift
Christmas Day and Good Friday are the two holidays most councils nationally adjust for, since both are non-negotiable public holidays that regularly fall on a weekday. Some councils also adjust for New Year's Day; many others run their full normal schedule through every other public holiday, including state-specific ones.
This is genuinely inconsistent from council to council — there's no single national rule, which is exactly why "just remembering" it is unreliable even for people who've lived in the same area for years.
How this app handles it
For every council we support, we track the specific public holidays that council has confirmed shift a collection, and by how many days — not a generic "add a day for every public holiday" assumption, since that would be wrong for most councils most of the time. Where a council hasn't published a holiday-shift policy, we show the unshifted date rather than guessing.
The clearest way to check whether an upcoming holiday affects you is the calendar view after searching your address — any shifted collection is flagged directly against the affected date.
If you're not sure
When in doubt around Christmas, Easter, or New Year specifically, your council's own website will usually publish a one-page holiday notice a few weeks in advance — worth a quick check if you're relying on a collection during that window for something time-sensitive.