In my opinion, no individual timeshare owner should ever pay the optional ARDA fee. ARDA works for the developers, not individual owners. ARDA has killed bills in certain states that would have led to more consumer protection from predatory timeshare developers and backed legislation (I.e. Florida) that led to decreased protection for individual consumers / owners.
ARDA makes millions off the "voluntary" donations of owners, and then turns around and uses those millions to protect developers, often at the expense of owner rights and owner protections.
Hypothetically, if every owner paid their $5, $7, $10 ARDA fee instead to some kind of Timeshare Owners Protection group, that would generate $50M-$80M per year and would give owners the funds needed to level the playing field against the developers.
Not all developers are the same. But some of the timeshare management / developer companies out there appear to have no conscience and aggressively exploit every loophole available to them to take advantage of owners. ARDA is not protecting timeshare owners, not even against those super aggressive predatory timeshare management / developer companies.