Do you have the knowledge and time to actively manage your investments yourself? Or do you want to invest in either individual stocks or bonds or more exotic investments?
Do you want diversified investments, but for a lower fee than you would pay a traditional financial advisor?
Could you use help affording a future expense?
Consider a robo-advisor.
Then you probably don’t need a robo-advisor.
Even if you have the financial sophistication to manage your own individual investments, you could still benefit from a robo-advisor that offers a diversified portfolio. However, if you don't wish to just be invested through ETFs, a robo-advisor may not give you the necesary flexibility.