If it bugs you....clean it.
If it doesn't bug you...don't clean it.
It's entirely up to what you are most comfortable doing or not doing.
I have/had a S9 heated hose that went through 3 different S9 machines with well over 10K hours of use...and I never washed it.
And I use a high humidity setting to boot. That hose got retired when I got the AirSense 10 machine because S9 hoses won't work with AirSense machines or else I would probably still be using it.
It is what I am comfortable with...and I am the only person that I have to please and I really don't give a rat's behind what someone else does or doesn't do.
Been on cpap a little over 10 years now...
When I first started cpap I did the weekly cleaning of EVERYTHING...that got old real fast. After 6 months my cleaning routine consisted of washing the nasal pillows when I happened to think about it. And I didn't think about it very often.

Back when I first started therapy we didn't even have heated hoses.
One thing I would never do is use a stiff brush on the inside of a heated hose. I would be afraid that the brush would damage the hose or heater coils.
Bottom line...you get to decide what you are most comfortable doing or not doing.
You are the only person that you have to make happy.
I may have to RISE but I refuse to SHINE.