This is my first Fire Emblem game (and I'm loving it, by the way). So keep in mind my status as a novice when I say this, as I very well may be playing it wrong...
...but I'm at chapter 13 now, and Frederick is still a beast in my playthrough. Everybody says he isn't useful as the game wears on, so I'm wondering how long this can last.
Also, not to step on Josh's toes, but there was a similarly poignant article on Kotaku about Frederick the Wary that people might enjoy.
I keep using him, and he keeps destroying things. so, idk. I'm only on chp12, and have done tons of grinding so I'm pretty op.