Took my 2-year old De Rosa Idol into the LBS for the annual tuneup. This is the first time I used this particular LBS.

I've always read that the BB and Headtube should be periodically disassembled and inspected and re-lubed. Well, the mechanic here said that on modern bikes with sealed bearings that the BB and Headtube should not be opened unless there is a specific problem that needs addressing. Then he pointed to a vintage Trek 1100 and said it's bikes like this that need periodic maintenance on the BB and Headtube.

So, whoopee, I learned something today. Are the readers in agreement with the mechanic's opinion?

One problem he's addressing for me on this machine is that the stem gets out of alignment with the fork. This happens on every ride, and also happens on a good technical descent like Deer Creek Road. This is a recent problem in a 2-year old setup.
Headset: Campy OEM Integrated Stem: Zipp carbon SL145

I don't know what he'll come up with, but my concern, beyond the inconvenience is that there is a crack developing somewhere in the system. I'd hate to be doing a 40mph descent and have the handlebar all of a sudden come free. Any conjecture here?
(not about my fate in that descent, but about the alignment problem)

One more thing. In this shop there is a "Tips" jar at the mechanic's counter. I never saw that before. Is this common? I have no problem with leaving a tip for the person wielding the wrenches, I just never saw it before. What's a reasonable tip, percentage wise.