Plan to live on about 4% of whatever your equities portfolio is because that is how much you'll be able to reliably draw from without touching the principle.
For example:
1 million = $40k/yr
2 million = $80k/yr
3 million = $120k/yr
4 million = $160k/yr
If you invest 15% of your income consistently in well diversified equities portfolio during your working years you should be ok at the end.
Don't count on social insecurity to be there.