An annual factory calibration certifies that your AquaLab is performing within specifications.
Additional reasons to get an annual calibration service -
With your annual calibration you can get an AquaLab Loaner Instrument to continue measuring water activity while your instrument is being serviced.
If you need to know the state of your AquaLab when it arrived at Decagon (prior to any cleaning and/or servicing), request an As-Found Report.