One of the selling points of a college like Knox is the ability of students to work closely with faculty, and independent study is one way this happens. It may be participating in a research group in a professor's lab, studying a subject not offered in the regular curriculum, following up a course with a more advanced research or creative project, etc. While usually done one-on-one, a small group independent study can also work well. The trick is to balance faculty availability with student demand, given that the demand is often high. The official language of the college catalog may be helpful in figuring the balance point:

Independent study is used to enrich Knox's academic program by providing students with opportunities for study that cannot be pursued in regular courses. While all students who would benefit from independent study are encouraged to pursue it, this opportunity may be limited by the faculty's obligations to the regular offerings of the College. Hence, independent study may not be used to duplicate in whole or in part courses regularly offered, nor may it be used for introductory work of any kind.

Besides being a great learning opportunity for students, independent study can be rewarding for faculty too--a chance to work closely with a student, to study together material you don't usually get to teach, to test out a subject that is a possibility for a new course offering. But will it interfere with your "obligations to the regular offerings of the College"? Only you can judge how much time you have available for independent studies in a given term or year. Some factors to consider:

How often you'll meet It is common to meet for one period a week, with the student working independently the rest of the time. (This can vary a lot according to discipline and nature of the project being undertaken.) Your own preparation time may be minimal or extensive, depending on the circumstances, so this too is a factor. (Some independent study is done for a half-credit only. Meetings can then be concentrated in the first half of the term, or spread out more sparsely over a longer period.)

The student's motivation Students will come to you with a variety of motivations. Some typical ones: interest in a specific subject, and you've been recommended as the person with expertise; interest in working more closely with you, having already taken a course with you; enthusiasm for the notion of doing independent study, but with little idea of what specifically to work on; a desire to build up some extra credit for no extra tuition (quite often the source of a request for a half-credit independent study); the notion that an independent study is an easy grade; the need for a specific course in order to graduate, one that is not scheduled to be taught at a time convenient for the student. (Yes, we know that this last category is excluded in the catalog copy quoted above, but such requests are made and some faculty say yes. The Dean's permission is needed to register for such.) Some of these motivations are more likely to result in fruitful time together than others. Be sure to talk with the student at some length before agreeing to work with him/her in order to assess their motivation and the extent of their preparation for the work proposed. 

Your own expertise You may know a great deal about the proposed subject, or you may know little or nothing about it. If the latter, and you also have no interest in learning, don't hesitate to say no! There is a limit to the subjects students will be able to study with a faculty numbering under a hundred. Sometimes you can suggest a summer program or off-campus program that will serve the student's interests better than an on-campus independent study.

So--how many to take on? Probably no more than one or two a term, but not as many as six in a year. (This can vary by discipline. Scientists who have students working with them as part of their own research will often take on more.) Again, only you can judge; there is no fixed number of expected independent studies. If you rarely do any at all, it might be a worry, but there is such a thing as doing too many also. Consider your circumstances. Are you teaching new courses or have a heavy preparation? Working hard to finish up a research project? Then you may want to say no to any independent study in that term. Balance requests for independent study with everything else: regular course preparation, committee service, departmental service, honors projects, scholarship, and professional travel--and don't forget your personal life! If you are a part-time or job-share faculty member, remember to divide the suggested limit in half. Don't get overextended!

N.B. Independent study courses are not counted in one's regular teaching load, nor are they remunerated (except in mini-term or during the summer, when a small stipend is paid). But there is a place in the cv update form to list the independent study courses one has directed, and it is taken into account when looking at the range of your teaching.