Federer turns 34 this year and Nadal turns 29. Their days at the top are numbered. While Federer is #2 right now, I think he will fall out of the top 5 permanently either this year or next, simply because his body will not be able to keep up with the younger players. I was expecting Nadal to stay top 5 for a few more years, but now I am not so sure. With his recent slump, how far do you think his ranking will fall this year? How he does in the French Open will be a huge factor.