Schedule 2 of the Commonwealth Electoral Act provides the grounds for application for a pre-poll or postal vote. Convenience is not one of the acceptable reasons. If you're pre-poll voting just because that seemed easier than queuing on election day, technically you're in breach of the Act and could be refused a vote. In practice, that happens very rarely (but I have seen it happen).

Voters love pre-poll voting, but political parties really don't, because they have to staff hundreds of early voting centres for weeks before the election. In 2021 legislation was passed to restrict the early voting period to no more than two weeks – previously it depended on the length of the election period.

Fun election fact: Early voting has just started for the federal election and last election was the first time that more than half of all votes were early. Early voting has increased in an essentially linear fashion since pre-poll ordinary votes were introduced, and so this year it will probably be well over 50 per cent.