Actually, iron is not secreted in the urine so taking too much for too long can be toxic. And if you juice, (especially if you use EQ) your RBC will be high anyway and too much can cause a stroke. Having said that, without sufficient iron, you'll never be as strong as you should. Also, ferrous sulfate (the type in most vit/min pills) is a lousy source. Taking desicatted liver is a good natural source.
Using a little supplemental iron as insurence is a good idea, but not every day. It should be "cycled."