The 2 robo-ETF companies mentioned basically have you set a risk tolerance level & then invest in a diverse selection of ETFs on your behalf. The company's job

The 2 robo-ETF companies mentioned basically have you set a risk tolerance level & then invest in a diverse selection of ETFs on your behalf. The company's job is to keep your investment balanced based off the risk tolerance level you suggested. So a risk tolerance level of 5 might mean your investment should have 30% of it in bonds. If your portfolio ever moves to 31% bonds it will re-adjust by selling some of your bonds ETF. Hence my comment about "invest in ETFs and forget about it". I believe the above mentioned companies also offer non-ETF investments for customers with over 100K. In this case instead of putting your money into an ETF, they basically buy the individual stocks that the ETF would have been tracking.