The Telstra Pre paid Max always used to have a 28 day expiry.
Now depending on the amount, you can get a longer expiry.
The problem I see is with scheduled recharge ie they charge you on a set date ie the 3rd or each month. This is ok with a $30 recharge but not with the larger amounts.
They have also increased the international countries included and now appear on the $30 recharge.
Competition must be driving this, their coverage edge isn’t enough reason for most to stay.
https://www.telstra.com/content/dam/tcom/personal/help/pdf/c…
This is similar to Optus new prepaid where it can go to 365 days for about $120 (Optus Prepaid Epic Value $180 for 60gb but in Eastland VIC, it is currently at $120)