L-Lens Weather Sealing breaking down?

I just got a new 24-105 and when I put it on my cameras, it's very snug (this is not a complaint). I looked carefully at my 17-40, which I use all the time, and noticed that the rubber weather sealing is broken in a few places. I'm also borrowing my friend's (who is a professional and uses his lenses 20x more than I do) 24-70 and noticed that his rubber is broken all over the place.

I'm assuming this is common. Is there a way to prevent this? Maybe some kind of lubricant?

...or is this uncommon and everyone's rubber is intact except for mine?

I hope this post doesn't sound too erotic.

The rubber gasket that seals between the lens and body is like any other elastomeric material...that is, it won't last forever. Elastomers dry out over time and become brittle, eventually cracking. I'm sure that you can get a replacement gasket from Canon. As far as lubricating it, I wouldn't recommend that...the lubricant film will just attract and hold dirt particles, which can find their way into the body and/or lens. Don't lube the rubber.