Can a Letter of Recommendation be effective without much coursework I'm applying to grad schools this coming fall and have 2/3 letter writers lined up, and am just trying to make a decision about the third. I took two classes with this third letter writer about two years ago, one survey course and one directed reading. We spent a lot of time in her office hours chatting and she got to know me as a student, and I achieved A+ in both courses.
However, both of those courses were two years ago, and we haven't had much interaction in the interim as I've been completing credits for my other major. I was planning to take a seminar with her this fall so as to get a third course in with her, and also one which is more recent so that I'll be fresh in her memory. But, the course conflicts with pretty much everything else I was hoping to take this academic year, including some courses much more directly related to my research interests.
Was hoping to solicit some thoughts on whether a LOR can be effective a) without much coursework and b) with not-so-recent coursework, providing that the coursework which was done was completed with great marks and lots of professor-student interaction. In other words, even with glowing comments, will a committee always look negatively on letters based on out of date courses (completed in 2nd year, for instance) and not that many of them, to boot?
Thanks
I think that a recommendation letter will be impactful even if the professor/lecturer writing it has taught the course or interacted with the student a decent time ago.
There are more important things pertaining to the strength or value of a recommendation letter (which is not praise from the person (since that must already be present anyway)) but things like:

The relevancy of the professor’s field to the field of your future work for which the recommendation letter is written for.
The amount of interaction with the person.
The current state of interaction with the person.
Any achievements that are recognized highly by this person and are mentioned in the letter (relevant to your area of study/work).

In general, the reason why it is not recommended to get letters from the faculty in your first or second year of undergraduate study is because they may be professors teaching general classes, which might not be relevant anymore or not specific enough to your current interests.
If however you believe that the work you did with a professor 2-3 years ago is still highly relevant to your application, then don’t hesitate to get a recommendation letter from them.