How to cite (Chicago author-date) papers your paper is about I'm writing a philosophy essay. The essay is required to answer a particular question by analyzing, in turn, four particular philosophy essays; the essay needs to follow the outline below.


Restate the question.
Introduction.
Analyze essayW by Mills
Analyze essayX by Shue
Analyze essayY by Locke
Analyze essayZ by Hospers
Answer the question with information from essay analyses. 


Where do I need to write (Author, Date) in my analyses? Each analysis will be about an essay, and will reference that essay in most of its sentences. Do I need to include the same citation in every sentence that references that essay? That seems like it would aggravate the reader.
I often see this issue when reading student lab reports in psychology. So for example, a student is paraphrasing a number of claims made by Smith (2000), so they write:


  X is related to Y (Smith, 2000). The cause of some stuff is blah blah (Smith, 2000). Then the system does that (Smith, 2000). But several reasons for this include A, B, and C (Smith, 2000). 


One problem with this form of writing is that it does not make explicit the link between statement and citation. There are many possible links between citation and statement (e.g., Smith asserted a claim; Smith conducted research and obtained a finding; Smith is one reference among many where a generally accepted fact in the field is asserted; etc.).

In general, if you are writing critical commentary about a particular article, then your writing style will need to be explicit about claims made in the target paper and what is your analysis. One way of restructuring the text is to make the author explicit in the text. E.g., 


  Smith (2000) proposed that X is related to Y. He found evidence that the cause of some stuff is blah blah. He went on to show that the system does that. He proposed  several reasons for this including A, B, and C.


Note the full in-text reference is provided in the first sentence. The remaining sentences make it clear that the propositions are related to the citation in the first sentence. Furthermore, the connecting words (e.g., "proposed", "found evidence", etc.) provide further information on where the propositions came from (e.g., theory, mere assertion, empirical evidence, etc.).