Vibration analysis or condition monitoring is recommended?

If you have a number of compressors on a number of sites & over the years have never given any problems, is there any justification for condition monitoring?

Do you use it to prolong overhaul or major maintenance intervals?

Is it best used for critical machinery in process plant, so if it goes down the whole show stops! I would say yes

In my experience compressors don't fail unless something is basically wrong with system, for example
liquid floodback
poor oil filtration & maintenance
high oil tempratures
diluted oil.

Generally speaking from my experience

9 times out of 10 slide valve is worn allowing rotors to contact , causing rotor tip wear.
This can be caused by general wear & tear.
5 times out of ten rotor journals are worn due to poor oil filter maintenance, blown out oil filters etc.

I'm not sure vibration analysis can prevent this happening even if oil analysis is carried out at regular intervals as well (more money).

I think laser alignment has generally improved compressor life as it simplify's alignment for people with basic knowledge & near enough attitude.

Interested in any comments & experience