Letter consultation is a way to actively seek help and answer questions from relevant departments or individuals. By writing to consult, you can get professional guidance and advice to solve your own difficulties or doubts. Moreover, writing consultation can also establish effective communication channels to promote the solution of problems and the smooth progress of affairs. In contrast, writing letters is more a passive way to reflect problems, and it may take longer to get a reply and solve problems. So, on the whole, writing letters for consultation is more effective and reliable.