I think the only time I watch an anime dubbed is if I expect it to be action heavy and I want to see the action instead of the subtitles.

Mecha anime, as an example. I want to see the robots and explosions, not the bottom 4th of the screen.

But nearly every other anime, I just watch it subbed. Also, if I start in dub and I find the character voices annoying, I switch to sub.