When using APA style citations, is it acceptable to have page numbers for everything? I am taking a psychology class. The professor wants us to use APA format for citations. I have read that if I am not quoting material directly, then the page numbers are not required. 

However, I think its bad practice not to cite page numbers. For example, when I cite my textbook, if I don't give a page number, the person would have to go through the entire book to find the passages I am talking about. And that just seems stupid when I could simple add the page number. But I am not quoting directly, so I'm not sure if it customary to incorporate page numbers like that.

My Question:

Any suggestions for what to do? I'm sure my professor is trying to get us to practice using APA style correctly, so I'm really just trying to find out if I incorporate page numbers for everything would that be outside the norm.
In APA style, when you cite a work, you add an in-text citation in the body of the work and you add the full reference to the reference list at the end of the work.


End of text references for book chapters, journal articles, and similar works include the page range of the work in the reference. This  refers to the start and end page of the cited work (and not to the particular pages that contain the content most relevant to your citation).
In-text citations need to include page numbers when you are quoting a passage of text.
APA stye encourages but does not require the use of page numbers in in-text citations where you are paraphrasing a specific passage of text (i.e., putting a passage of text in your own words). That said, I rarely see this practice in journals, and don't be surprised if someone marking your paper is unaware of this rule.
The more common rule is that if it is not a quote, then you don't use page numbers in in-text citations.


Rationale

As @Josh points out, most citations in psychology refer to overall works. For example, a journal article may present the results of an experiment, and these results and communicated and discussed in multiple points in the article. Thus, you are citing the work as a whole, and it does not make sense to refer to specific page numbers. 

That said, I think there are times where authors cite an entire book written by one author for a reference, and some form of page reference would make the citation more useful for the reader (e.g., a particular chapter might be most relevant).

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Purdue OWL APA Format