Welcome to our forum.
Ease of maintenance.
There have been a number of occasions when I've repaired a spa with pressurized or 'in-line' filter systems where the filter cartridge hadn't seen the light of day in years. I even had the response of... "Gee, I didnt even know that was there...."
I work in the medical repair industry and people will destroy things IF it's not brought to their attention. As a tech, I bring it to their attention by hitting their pocket book when it's appropriate. (Someone drops something for the second or more time). For those of you who have to "fix" a dirty filter, maybe a reminder that this call was free and the next time it'll be billed at $( fill in) per hour travel and labor because of operator abuse and operator error.
I was assuming that these calls would be covered under the tub's warranty (1st one of this type). Hopefully this problem is a newbie problem and not an ongoing problem.