What Debris Have You Seen in a Transmission Filter?

[shertex]

I have always had my indie change my transmission filter. I'm told it always looks pretty clean. For those of you who change it yourselves, what have you seen by way of debris after, say, 30,000 miles?

Part of the reason I ask is that I've gotten in the habit of changing my fluid via a topside extractor with somewhat greater frequency. (I'm not able/willing to change the filter/gasket myself.) Thus I leave the filter in place longer than 30,000 miles. Just curious what's accumulating there, and in what quantity.

Also, whatever is getting trapped by the filter, does it drop into the pan when the fluid isn't circulating? Therefore would I get at least some of it out by extracting?

Thanks.