It is very easy to ask questions that only tangentially involve 3D printing, such as:
How do I drill a hole in a 3D printed part?
How do I paint 3D printed parts?
How do I sand, smooth, etc...?
How do I take a picture with a 3D printed camera?
My last example is clearly not on topic, and the other examples aren't
difficult, specific questions — the kind of questions pros and experts ask each other, not the kind of questions novices ask pros.
However, the point is that it's very easy to involve 3D printing in a question that isn't about 3D printing. Drilling a hole in a 3D printed part is, for the most part, just like drilling one in wood. Such questions may be more suited for a general DIY/makers-type site.
On the other hand, there do exist 3D printing specific issues (for instance, low infill or delamination can be a problem when drilling in a (FDM) 3D printed part).
At what point does a question involving 3D printing become on-topic for our site? Should questions identify a specific issue ("I've tried drilling a hole, now my part has delaminated, what now?")?. Queries for general advice and best practice don't seem to fit the bill of being difficult and specific.