The best way to use compact fans - we recommend - is the application of ball bearing motors.
Those fans have a so called L10 of approx. 50.000 hours.
This means that after that period of time an amount of at least 90% of the test objects need to run still faultless. Ball beared fans may be used in all X/Y/Z axis.
Fans with one or two sleeve bearings inside their motor are empirical a little bit cheaper to have but show a shorter life expectancy.
In a no continous service operation the application should be trouble-free.
Fans with sleeve bearings should be mounted in an upright position but may be allowed to use with "hanging" rotor as well as in a horizontal position.
Possibly fans with ball bearings are a little bit more noisy than expected. But after a while of use the sound will be softer and more gently.
Some of our customers have TIGER fans still today inside an apparatus under permanent operation
since 1997 (!). This means 19 years x 365 days x 24 hours = more than 166.000 running hours.