Thanks all!  
And to address the do I need it after 2 years.... Possibly not.  But if I see something that even resembles a crack I touch it up.  Along the front seam it seemed to be showing signs of some hairline cracks so I just ran a new bead across.  Seems like there is always a small spot here or there that looks like it might start cracking so I have just been adding from time to time.  I probably overuse it which is what prompted my question.  I had serious water damage in a previous camper and it destroyed the camper so I am a bit over cautious I suppose.