Bently Nevada XL Vibration Probe and its Life?

Hi Everyone!

I have these two questions in my mind; first of them is what exactly the term 'XL' means? I have read so much about this probe, but can't seem to find the acronym for XL. Also, I have heard my co-workers say it is an acronym for Extra Layer, since there's an extra braided protection layer on the outer most braid wire of the probe's coaxial cable.

Second Question is about life of these probes; so, how long do you think they should work? At my workplace, they will get it replace whenever a machine is overhauled for any reason, even though the probes were working fine.

Help will be appreciated, Thanks!