Yeah Nut - I've noticed the same thing. The cleat on my "stopping" foot especially on the road shoes which don't have tread around them to protect the cleat seems to fit the pedal a little bit harder these days and sometimes takes a real "push" to get it to click on. Now that Denise et al have mentioned - it's been almost a year since I started wearing cleats - so I'm guessing it's about time for me to change them out.
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"