One of the common close reasons we use on Bicycles.SE is "Questions seeking product, service, or learning material recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve."
I'm not sure that closing service or learning material recommendations really fit in with the first one (product recommendations, which do get obsolete quickly). Lots of learning material (Park Tool's guide, various books, etc.) don't go out of date on bicycles, and how to service some things is quite tricky to deal with. Of course, requests for learning material and service material can be too broad, but we have a separate close reason for that.
I think re-wording this close reason to be "Questions seeking product recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve."
Thoughts?