I'm guessing that your shoots have objectives? eg, you know what you'll be shooting and you're after specific shots and you know the circumstances in which they'll take place, so you know what lens(s) you'll be using.
Whether I'm conforming to standard photographers practice or not, I don't know and don't really mind. I like the telephoto's ability to get up real close from a distance or pull back to 200 and capture a reasonable wide image. The 400 does this beautifully, for me anyway. I can take a portrait from twenty metres or a landscape, back at 200. I'm also interested in aviation and the 400 is excellent for that. I've also got a 24-105 and at the moment, the only other lens I'd like is probably a wide angle.
Mike.
PS I know it's another thread but had to mention it. Just read the Light Field Camera thread (Lytro)
Light Field camera | Lytro Anyone wanna buy my Canon now? (kidding)