My larger projects have over 1000 clips. What I found to be helpful for me is to use the "Good" check mark for the clip in the browser. Check it when you use the clip then you can see it right there at all times. All the clips that aren't checked are obviously not used. I always type "good" in the log notes while logging footage and usually get more descriptive than that anyway.
Before doing it that way I was changing the label color of the clip to show it was used but that takes to many keystrokes and clicks compared to clicking once.
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