At what drop in the market do you consider it worth your time to tax loss harvest? Five %, ten% or 20%. For some one who automatically invests every two weeks into v t sacks and v t ia x. Does vanguard allow you to make all those tax loss harvesting transactions in one day? Greater than 20? A basically, dollar amount is really what i pay attention to. Percentage matters, insomuch only if it's a significant dollar amount. You get most of the bang for your buck out of doing this once every three or four or five years. It maximizes time in the market. And there's a lot of benefit to having an automated investing process.