If an individual reads a broad range of reports on Op Amp usage their is usually to be found the Strong Suggestion a Op Amp needs to have approx' 100 hours of usage to get to the place they are sounding even and coherent across the frequency range.
I stand by this 100 hour requirement as the suggestion for the Burson V6.
Swapping out Op Amp's with a short term usage as the demo' period is most likely to produce an incomplete assessment of the Op Amps capability when used in a particular circuit.