I was told a lack of grease can cause a vibration. I had some vibes and then I repacked the thrusts and the vibes toned down a bit. So I would check the grease in the bearing and see if they are packed well.
Lack of and use of wrong grease can cause vibration
That applies to all birds
The dampeners need the right grease on them (silicon grease from a plumbing store) to make sure they are smooth and don't have a VICE grip on the feathering shaft. In flight the whole system centers out itself. If your bearings are not packed and dampeners are holding on to the shaft under load with a death grip that's just asking for imbalance .. As the blades can be upto 1mm off in flying radius.
When I say right grease.. For all people not familiar with the fact this a hydrocarbon based oil or grease will or can make your dampeners swell up. Swollen up new dampener is add bad if not worse as a used up broken or worn out one. So
No bearing oils no oils in general. SILICON GREASE .
Thrust bearings should be packed with good lithium based grease (I think) I just got thunder tiger thrust bearing grease .. Black stuff
Yes thrust bearings can cause vibrations if they are rubbing up on the shaft, or have a ball out or something failed of have rusted and again are causing a horizontals bind in the system
Nope they don't need replacement every 20-25 flights. They need packing when installing and cleaning when repairing and replacing till you feel like they need replacement .
Last two and a half years on my 450 I replaced them once.. That too cause I lost the covering of one side for one
As far as installation.. Make sure to follow the Manual on what ID goes where.. Big inside or small outside.
My tracx head is small ID in towards the head yoke
I think align asks for small ID out... So yeah the head .. The part that makes you fly.. Needs to be built meticulously and greased and lubed ..
BUT
If it ain't broke don't fix it!
Fly safe!!

have fun!