As someone who has answered questions in this category I will respond with some of "my" reasons. There are times when I list my credentials.....Master Gardener, Landscape Designer, Lawn/yard/shrub Business for 10 years, a lifetime of gardening experience, and others. I do this when I think it may let someone know that what I suggest is time proven and is the Best solution I know, other times I list nothing, knowing that years of experience will make little if any difference since common sense can be the judge. In the end it is still the asker who picks the answer best suited to his/her problem and all the Degrees in the World do not necessarily make a person the best of the best. I strongly suggest that anyone asking a question get a second opinion, there are many places with a wealth of information, such as your local Agricultural Extension Office, Libraries, Nurseries etc.