If I am writing a letter of appreciation for the performance of a front-line enlisted person, how high up in the chain of command is the most appropriate level to send the letter? I know LOAs are often very important for military members, and can potentially have a positive impact on promotion or awards. I would like to provide this person with the maximum benefit for doing a good job without being inappropriate about it. Obviously I'm not going to send the LOA to the Chief of Staff or anything, but I wouldn't want to send it to the lowest direct leadership if it should go higher.