I've been using Spam Sieve for the last few months. I get a lot of spam. It catches most of it.
But I get a lot of spam, because my email address needs to be widely available. That means I can get 90% spam rejection and still find myself with a hundred spams overnight.
Do I need to train it more — even though my corpus is already too big? Do I need to retrain it? Am I expecting too much?