I am happy to write letters of recommendation for any student who has done well in my courses.
I do ask the following: for any letter of recommendation you want, give me some lead-time for writing it.
For letters of recommendation other than for LSAs, please keep my commented copies of your papers . Then when you mail me the recommendation form, please give me copies of your work. (Alternatively, you could scan them and keep them on your hard disk.)
The reason is this: Letters of recommendation are more effective the more specific they are. It may be distressing, but though I may remember a student perfectly well after the passage of years, I may have forgotten what his or her strengths had been.
If you give me commented papers, I can write "I see that Mary is particularly good as describing difficult concepts in clear language," or "Bob is quite good at structuring complex arguments," which is much more effective than, "nice person, great personality, good dancer etc."
So please: If you think you'll be asking me at some point for a letter of recommendation, keep your work from our classes handy, rather than stored in granny's basement with her preserves. It will make my work easier and more effective for you.