Pop, Pop and Pop and I figured it out!
 

Bicycle noises drive me crazy. This past week one started up. Could actually feel the popping in my pedal. I couldn't imagine that the cleats had already worn out; but, low and behold, that was the culprit. I am using Shimano SPDs. I am a little surprised that they wore out so quickly; but, I guess time flies when we are having fun. I try walking on my toes and/or take my shoes off when I take a break. This was one of the main reasons I switched from the Looks as the cleats also wore out quickly. Maybe I should just start putting ear plugs so that I won't hear the creaks, pops and other aggravating noises. (Main reason I couldn't ride a mountain bike.

I didn't know that they could wear out? I thought that's the reason for having recessed cleats.

They don't wear out from rubbing on the ground, but from clicking in & out. Each time a little metal is scraped off the cleats by the pedals. Sure, it's not a whole lot, but over time, the cleat does get smaller.

Try walking on your heels.

how many miles did you have on your SPDs before they gave out on you?

I don't think walking wears SPDs at all in any way that affects their performance. The surfaces that are relevant to retention can not possibly touch the ground. I've been walking around in SPD sandals pretty much every day for most of the day for the better part of a year, and they are still functioning perfectly.

I am talking about the SPD and I guess maybe SL. It does not have the recessed cleat. It is the plastic cleat similiar only thicker than Look. Sorry for the confusion. But yes, I try walking on my heals.