You may have heard the old saying ,"The cobblers children go barefoot," which signifies that those involved in any certain profession might tend to neglect whatever it is that they work on, in real life.
"The plumber has leaky pipes."
Add to that, "The mechanic's bike is in sad, sad shape."
When I worked in a shop, most of my day was spent working on bikes, in one capacity or another. If I wasn't doing a repair, I was building up a new bike for the sales floor. Or, perhaps, I was fixing a flat, or adjusting a bike to fit a customer.
At the end of the day, I really didn't feel like working on my own bike. I would lube the chain, and check the dreailleur and brake adjustments from time to time, but basic maitenance tended to go by the wayside.
Case in point: One day, as we rode back from the Park Meadows breakfast run, I noticed that my bottom bracket was making some noise. I was on my Specialized S-Works M2 mountain bike, because it was handy. I had ridden it, the night before, and left it in the back of the truck, when I got home. So, it was right there, when I pulled into the shop parking lot, that morning.
I stopped, and got off the bike, to spin the crank backward and see if I could figure out the mysterious noise. I had a cartridge bottom bracket in the bike, so I knew it wasn't an adjustment issue.
As I knelt down and spun the crank, I tipped the bike slightly toward me. When I did, I saw water dripping out of the bottom bracket shell.
"Hmm," I thought to myself, "when was the last time I rode through water?"
I remembered, as we rode back to the shop, that we had made a number of water crossings, the week before, on the club ride. Surely, there wasn't still water in the frame after that long...
I put the bike in the stand, once we opened up the shop, and removed the cranks. When I pulled the bottom bracket cup out of the non-drive side of the shell, about a cup and a half of creek water spilled out onto the shop floor.
After bathing for a week, even a Shimano UN-72 bottom bracket will be infiltrated with moisture. The bottom bracket was toast, so I installed another.
Maintenance by repair is the hallmark of the working mechanic.