I went down more times than I like to count and am convinced the riding-specific boots have prevented my ankles from being broken, and I've had some really nasty crashes.
As for pants, let me say that I've gone down at ~5mph and it was as if the jeans weren't even there. Some nasty roadrash left scars on both my knees. That said, if you opt to go that route anyway, then I recommend choosing the darkest colored, least "washed"/"worn" jeans you can find. The lightening process denim manufacturers use involves putting the denim into a huge bin with rocks and water and running them 'round and 'round, thus thinning the material while giving you that light, used look. For crashes you obviously want as much material as possible.
There are denim-style pants specifically for riding if you're really concerned about image (understandable for certain circumstances). Check out Draggin' Jeans as one example. There are more than a few others.
Dragging knee is for the track, and dragging tail is for the lot. --Kane Friesen
When you're in a car, you're watching a movie; when you're on a bike, you're in the movie. --Robert Pirsig
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