[MENTION=218808]Jaywalk3r[/MENTION], you've had worse than average luck. I have had a pair of Bluemels (made of plastic) for over 30 years. They're pretty battered by now, but they're still there. I would expect a pair of fenders to last 20 years or more with normal care.

[MENTION=21724]cyccommute[/MENTION], I love how your perspective is based in deep experience but comes up with an unusual conclusion. More power to you. My rough guess is that fenders reduce water and grit by two thirds. If your hope was for them to eliminate that stuff perfectly, you were set up for disappointment. If 2/3 improvement isn't much to you, that explains why they're useless to you. In a long heavy downpour, I'll get totally drenched with or without fenders, but I don't encounter them often, and I don't head out into them deliberately. But there's no question they keep me and my bike cleaner than a lack of fenders does.