[time-nuts] What to expect from rubidium lock behavior?

[Erik Kaashoek]

My rubidium frequency standard (Accubeat AR60A) finally got its nice box 
with good cooling and some LED's showing the status.
While watching the unlock LED I noticed the AR60 say's it is locked, 
about 4 or 5 minutes after cold start, when the frequency error jumps 
below about 1e-8
It takes 2 or 3 more minutes of slow drift to become stable within 
1e-10. Is this to be expected?
With this locking speed it is tempting to switch off the AR60A unless 
needed for some measurement. Would daily switching on/off have any 
impact on lifetime?