It's very flattering when someone who I've been coaching asks if I can serve as a job reference for them. But, over the years I have become more and more particular about doing whom I'll vouch for. Part of the reason is time. I've found I don't have the bandwidth to write arcane letters of reference, formally drafted "to whom it may concern" or to "members of the committee." Then, fold it in thirds, find an envelope, address it correctly, find...