Hi, Morgan. I am new to this site so be patient with my answer. I feel that the best part of belonging to an association is the connection to others in our field. It really is not about impressing your clients with letters after your name. I think of it in the same way that a doctor or lawyer would think about their membership in the AMA or the ABA. My association keeps me connected with what is happening in my industry and allows me to connect with other members on a professional basis. I learn much from the other members and am able to share my experiences, also.
I took care of my aging parents and as a builder/instructor, realized how much I didn't know. So, I went back to school. USC has a great course on accessible home modifications and I earned my Exec. Cert., but I haven't gotten a single job because of the letters. I, also, saw the need for electronic monitoring for elderly and handicapped - so I got a certification there, also. The point is, it's for you to really know what you're doing in a field of interest. I'm in a rural 'out west' area where word of mouth is even more valued than 'letters behind your name' and I know the satisfaction of truly doing it right. Test my theory at the next Habitat for Humanity build day. They believe in 'visitable' housing.