How long should a pair of SPD pedals and/or cleats last? I have have a pair for about 2 months now and I don't have the tension on the pedals that I used to have. I use to be able to ride without any shifting of the cleat in the pedal when I am pulling up. Now, I can feel a slight "give space" whenever I pull up. Is this a nuatural "give space" and I have only begin to notice it? or are my cleats wearing out?