I have been an ASTM member for about 30 years. - While working for a company or as an individual.
My previous employers (concrete products producers) always allowed me to participatee in ASTM since the indiviual dues were a genuine bargain and the attendance at meetings was optional at my discretion/reason for attendance. They also permitted full particpation in any professional/industry organization, which is common in this industry since professional activity is an absolute necessity, especially since the international influence/ownership of the concrete industry.
Just joining as an individual is easy and cheap (guess about $85 - $100) since you get a annual membership, a free book of standards (now on line), a discount on literature and access to any committee you are interested in.
Getting on a committee is easy. Getting a voting membership can be very difficult. Because the voting members are balanced a "little old lady" (interested party) may have a much easier change of getting to review, critique and actually vote on standards. This is partially due to there not being any real benfits of being a corporate member, other than supporting the organization and concept. It never hurts to attend meetings.
I was on a waiting list to be a professional voting member for many years because of the balance restriction, but fortunately, my activities in ACI, MJSC, NCMA and TMS somehow got me into a voting posuition.
The committee meetings are held twice a year for 3 to 7 days (many subcommittees and scheduling conflicts) at locations that tradtionally are in nice places with high room rates. The benefit of the commitee meetings is the opportunity to meet with others with similar interests and network with them. Many times I have seen the "little old ladies" be present at an important ballot that has been refined for a year or so, but voting agaist a change since other voting memebers have left after spending too much time when the approval was assumed.
Now it is not necessary to attend the meetings to vote. If you miss two consecutive votes, you can lose your rights. All ballots are now made on-line with a good system for information and voting.
ASTM is a bargain if you have an interest in one general area of expertise and want to be active in it. If you are a generalist, you may not find a home if you want to have a say. - At worst, you pay your dues and get a $100+ book of current standards.
Dick