The Australian Tax Office has increased the threshold at which you must hold a tax invoice for claiming GST tax credits.
It used to be that to claim a credit for an amount over $55 (including GST) that you had to have an invoice, but for amounts below that cash receipts ot some other proof of purchase was good enough.

Now the threshold has been increased to $82.50, or $75 excluding GST.

Check the ATO website for more details.