I would like to apply to grad schools next Fall. If the school requires 3 recommendations, is it ever a good idea to include more? Also, what do you guys think about including a CV?
Ever? I am sure there is some alignment of the planets where the plus of the 4th letter overcomes the minus of "cannot even follow simple directions". But I can't think of any.
Your best bet is to follow as precisely as you can the application procedure.
You don't get bonus points for having a fourth reference.
Most applications will, require you to essentially submit your CV in one form or another. Some will ask for it explicitly. Others will have you fill out a form that contains about 90% of what would typically be on yur CV anyway. So if you're asking whether it's a good idea to put one together at this point, the answer is yes.