Regular cleaning prevents build up on the image sensor of materials such as dust, label adhesive, inks and oils which can deteriorate scan quality. Re-calibration will help revert the scanner back to original specifications and resolve most image quality issues. Generally, the best indicator of a needed cleaning will be the appearance of any black streaks that may develop on your scanned document. For optimal image quality, we recommend that Ambir scanners be cleaned and calibrated approximately every 1000 scans, or about every two to three months for an average user. Heavy use applications may necessitate much more frequent cleaning and calibration.