I am not sure what my 'percentage of returns' really is, but I do tend to return in-store purchases a lot more than I do online purchases. I know this isn't the norm, but speaking personally - I am much more likely to purchase too much "stuff" the store, and I also tend to get sort of taken in by sales.
This doesn't happen to me nearly as much as with online purchases. With online purchases, I've done my research, I've read the reviews and I've probably been thinking of buying the item for quite some time before actually buying. In short, I'm a bit more patient with my purchases when buying online than I am in-store. When I'm in a store, I tend to buy a lot more, but then get home and realize that I've made several mistakes and a lot of it goes back. This isn't true for me with online purchases.
I also find that Angie's recommended products are a very good choice. There isn't anything that Angie has recommended (whether it's a NAS-type product or a fab find) that I've bought and then returned. She often posts additional helpful information - based on her experience with clients - things like whether to size up or size down, if a certain heel height works, or that one of her picks works particularly well for certain body shapes and so on. Meanwhile, I also find YLF'ers input extremely helpful as well. I've bought things that other YLF'ers have posted that worked out nicely for them, and these have worked out better for me than just blindly buying things in a store during a sale.
In short, I am much better-off with YLF guidance! In the store, I tend to buy too many things and then end up returning way too much of it. When I check in with YLF, read recommendations, and look at people's WIW's or questions/ideas - it helps a whole lot and as a result, my 'rate of returns' has actually been going down. My online purchases are more considered and thoughtful. I've seen them recommended by Angie or another YLF'er, I've done my homework and carefully made up my mind.
In store? Ack! I'm not very good at it. Buy a whole bunch of stuff, get home...wonder what I've done and what in the world will work with what I've bought, realize that I've purchased a bunch of "stuff" (ie. orphans) and end up returning almost all of it.