If the stock market gains 10%/year, that means doubing roughly every 7 years. Once your stocks/ETFs/funds have doubled, even a -50% drop won't incur capitali losses. Over time, most of your money simply can't benefit from tax loss harvesting. So you're paying their 0.35% fee on your entire portfolio, but only the last few years have any potential benefit from tax loss harvesting. So a tiny fraction benefits, and you pay their fee on the entire portfolio. Not worth it in my view.