Assuming an average APR of 6% on S&P ETFs (600000*6/100)*10 = an extra $360000 before tax. Probably not enough to retire on. 20 years is an extra $720000, let

Assuming an average APR of 6% on S&P ETFs (600000*6/100)*10 = an extra $360000 before tax. Probably not enough to retire on. 20 years is an extra $720000, let's say half goes away for tax that leaves $360000 + initial $600000 isn't even a million yet. $1m might be enough to live off on, assuming a APR of 6% ppa, so $60,000 money influx just in interest, but it depends on your standard of living. If you're used to a $100k+ engineering salary, it's a downgrade.*