Depends on the shows. I watch shows raw when I really really like the show and not only can't wait for the subs, but like the show enough that I'll want to watch each episode a few times.
And I've found that while I can watch school life shows raw and get like 90% of the dialogue, that gets flipped around with mecha shows, where I'll be like "Ohhhhhhhhhhhh, now wonder that didn't make any sense. I thought that they said 'port quantum cannon' and that's why I couldn't figure out why the beam was coming out of the right side of the battleship."
Oh, and I can't watch Haruhi raw because everything will be fine and then Nagato will start talking and I'll just have to give up and wait for the subs.
It took me probably a good year and a half of college Japanese before I felt comfortable watching raws. In total I've had 4 semesters of college Japanese so far and while I'm not taking any right now (it's not covered under my Masters program but hopefully will be under my Ph.D. program), I've also been watching/reading mostly raw anime, Japanese-language mangas, and playing the occasional Japanese-language ADV game (like the Sakura Taisen and Muv-Luv games) for the past year so I've been expanding my vocabulary (and kanji!) and keeping my comprehension skills sharp.