This is a group effort by Australians on the forum.
WHAT
0. Pay the minimum required on all debts.
1. Establish an emergency fund to your satisfaction. See
https://www.bogleheads.org/wiki/Emergency_fund. Use your mortgage offset account OR use springy debt
http://www.mrmoneymustache.com/2011/04/22/springy-debt-instead-of-a-cash-cushion/ .
2. If your taxable income is less than $54,837 (before salary sacrifice) consider contributing $1000 per year to superannuation to get the Government co-contribution.
3. If you have a HECS/HELP loan, and the indexation rate for the year is higher than your wage increase, consider paying the difference.
4. Pay off any debts with interest rates above your mortgage rate (if you have one).
5. Put money into your PPOR mortgage offset account (if you have one).
6. Pay off any debts above the return you can reasonably expect to get on your investments.
7. If you taxable income is more than $18,201 optimise Concessional Contributions into Superannuation - you need to work this out individually, because how much depends on at what age you plan to retire, how much is already inside/outside superannuation, and your marginal tax rate. You also need to consider whether you want to take advantage of the First Home Saver Scheme.
8. Invest any extra into low cost index funds (long term investments - 10 years) or high interest accounts (short term - 2 or 3 years).
WHY
0. Don't get yourself into trouble.
1. Give yourself at least enough buffer to avoid worries about paying bills.
2. When the government is giving you money - take it.
3. This will stop the HECS/HELP debt from increasing faster than your wage. For example, the rate for 2022 was 3.9%. If your wages increased by 1%, consider paying 2.9% of the loan. This should be done before the cut off date (currently 1 June).
4. & 5. Because it's untaxed, the effective return on a mortgage offset account is likely to be the highest percent return you can get on your money
6. It's better to pay off expensive debt than to invest. Look up returns on Australian investments over the previous 10 years - for instance
https://moneysmart.gov.au/how-to-invest/choose-your-investments has investment types and returns.
7. Concessional contributions are taxed at 15% as they go into superannuation and people on low incomes have a lower tax rate. You will need other money to last you between when you retire (if you retire before you can access your superannuation) and when you are eligible for superannuation. However superannuation tax rates are low. You also need to be aware of the superannuation caps.
8. Because earnings, even if taxed, are beneficial. If you are saving for the short term (eg. a house deposit whether PPOR or IP), you want to be absolutely sure that you will get back what you saved, but longer term savings are better off in an index fund. If you are saving for a PPOR you may prefer to use the First Home Saver Scheme in superannuation.
https://www.ato.gov.au/uploadedFiles/Content/SPR/downloads/FHSSessentials_n75457.pdfNote: This assumes that you are employed. If you are a business, make sure that you put the superannuation guarantee (10.5% in 2022/23, 11% in 2023/24, 11.5% in 2024/25 and 12% thereafter) for yourself because if the business fails, you will at least have that money in old age.