The best way to answer this is to understand your living and lifestyle habits and identify if your income meets your expectations.
If you are a home-owning couple and you both expect to live to age 85 and say your investments will return 6% per annum, after costs.
If you had a combined $650,000 at retirement, your investment balance could well be Nil at age 85.
If you want to retire at 50 your day-to-day expenses will need to be funded from personal savings or other investment income.
To qualify for the Centrelink Age Pension a person must satisfy the residential qualifications and have reached pension age. The current qualifying age for a male is age 65, gradually increasing to age 67, the pension age for women is also progressively increasing from 60 to 67 years.
Therefore retiring early will mean you will be unable to draw an age pension from Centrelink.