Are you keeping it clean?  Dirty balls never keep their reaction that well, unless you're talking about one with the Soaker coverstck from Dynothane.  A healthy resurfacing may bring back the reaction you once had.  

Mine still gives me a good reaction, but I clean my stuff weekly at least and do light resurfacing almost monthly.
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American beer is like making love in a canoe. It's f*cking close to water. - Monty Python

Why is American beer served cold? So you can tell it from urine. - David Moulton