Limits on one student using all of one's office hours? I generally don't have a lot of business in my dedicated office hours, but then sometimes I get a needy student who wants to use all of them -- every minute, of every day, in which I hold them. It gets physically tiring for me, and emotionally draining that they apparently have no capacity or confidence to follow along in class, read the book, or make connections on their own. 

Granted that we have, say, 3 hours of office time per week (required at my institution), is it acceptable to set per-student limits on usage of that time, such as: 20 minutes per student per day? 

Additionally, is it advisable to be forthright and tell the student that their behavior is unusual/a bad sign/an abuse of the office hours; that is, that they should be mostly responsible for the material on their own? (Often this same type of student will praise themselves aloud for being so proactive/smart with the office hours when others aren't using them.) 

This is in the U.S., and I'm at a large urban community college. Assume that most of the time no other students are showing up to the office hour. 

(This was mentioned in this question and comments therein; I'd like to see a canonical answer on just this aspect of the situation.)
I will argue that setting limits for a particular student is acceptable and in some cases necessary. It really is an abuse of office hours if one student is taking up all of them, every day. Let's say that proper usage is around 10-15 min for a particular question or issue. For a particularly weak student like this I may assert, "Let's say we have 20 minutes for this." Require that she ask about a particular homework exercise that she can show prior work for. Do not just regurgitate the lecture wholesale.

By default, students should be able to master the material via lectures, study, and homework, without constant additional hand-holding by the instructor. Part of the unfairness here arises from the fact that the student is effectively getting double face-time with the instructor, relative to other students; so the one student's success does not really represent the same level of proficiency as shown by other students. Some other students may possibly take note of this, and either avoid office-hours interactions (which would be more fruitful) because of the always-present student, or silently resent the double-attention. 

If the instructor (like me) is becoming physically and emotionally drained by these constant interactions, then we should learn to be sensitive to that, and take that as a signal that some change or boundary needs to get set, lest we become burned out. There is, in addition, a possibility that the student thinks they are socially flattering or flirting with the professor for a better grade. It's probably a good idea to document these interactions, in case the needy student (or anyone else) is prone to complain later about their grade or some other matter. 

Under the "honesty is the best policy" principle, it's probably good in theory to have a frank discussion of expectations for the course with the student around the second or third time this happens. (But: I don't think I've successfully executed that to date.) 

The real tough case for me is a student who officially meets all the prerequisites to the course and points to the first day's lecture notes and says something like, "I have no idea what any of these words mean." Perhaps they got through all their prior courses in a state of acclimation to exactly this level of double-hand-holding. 

(This answer largely restates my answer and comments on that issue from this question. Thanks to the commentators there for refining my thinking on the issue, and thanks to @scaaahu for suggesting I write them up as an answer here.)