I am 54, and was able to "retire" at 52.
This was mostly accomplished through owning and then selling a small business.
While owning the the business we diversified into properties and shares, and since selling the business we have diversified further, mostly into more shares.
Starting early, and "having a go" at property and shares allowed us to experience first hand the value and power of being an owner of equity.
It also demonstrated the power of debt and of using other people's money.
There were some hiccoughs along the way such as the GFC, but, as we all know, the direction of the chart of the ASX 200 Accumulation Index, and the price chart of Australian Capital City Property has been a steady upward climb for a long time.
We were very nervous when we sold the business as it had treated us very well for a long time, but protecting our asset base through diversification was the aim, and so far, the plan has worked.