Let me give a slightly 'stronger' suggestion: when in doubt, make more questions, not less. I think that almost always when you could decompose a question into two good questions, you also should.
Of course, a question should be such that the answers are 'complete', but whenever you think that you have follow-up ideas or thoughts merely tangential to your current question, I think these are best served on their own.
I have a few arguments in favor of this idea:
We are not in the business of writing an encyclopedia. When someone visits a page on this site, they should get a good answer to the clear question stated on the page. They shouldn't get a survey of some topic (unless that is the question, of course) or barely related comments.
Asking questions is free. As long as the question is a fine independent of its 'inspiration', asking it does no harm.
Asking several related questions has the advantage of being more useful for 'future visitors' in the end. Suppose you ask the closely related questions A,B and C. If these are all asked and answered in a single question, a future users who only wants to know C might have a difficult time in understanding the answer (perhaps there is an easier way to explain C in the case that A and B don't have to be explained) or at least needs to filter irrelevant information. If the questions are asked separately, but still linked properly, we satisfy both the user that only wants to know C and the user who wants to learn A, B and C.
Of course, this doesn't mean that each posted question should have strictly one 'actual question', but I am in favor of decomposing questions into the 'least postable unit' (what this is depends on both the user asking the question and the community!), to ask many small questions rather than one big one.