As a layman, how is this different from just buying FZROX automatically every week for the next 30 years? No snark, trying to learn for my financial future!
Fidelity makes their own indexes for their zero-ER products, there arent any funds with the exact same holdings that I am aware of.
That being said, FZROX should track the broad US equity market pretty closely, so some of double's offerings should have very similar performance.
Double will let you do some additional things though. For example, lets say you wanted a US equity index with no exposure to the large tech company you work for. Double could do that, FZROX could not.
