while it is true that defragging will introduce more write operations to the storage, the frequency of defragging required to maintain good drive speed is not so high as to be detrimental to the hardware (once every six weeks or so works well for me)
While it may seem that solid state storage will not gain performance from defragging this is simply not the case. a quick benchmark of your own hardware will prove that there is a boost gained from defragging your storage.
here is an article posted by someone that reflects my own findings and clearly shows an advantage to defragging your solid state storage.
I know it seems illogical that solid state should benefit from a defrag and this myth seems to be further propagated by people who have not tested the benefits themselves, but i have tested and know there is sometimes a massive performance boost (over 40%)
http://tony72.googlepages.com/ppc_frag