I worked 12 years in industrial maintenence,I needed accurate electrical mesurements for processing equipment that measured weights-liguids(10,000 gals in a few minutes) and temperarure & time. We used the best multimeters we could find,the same with our specialized test equipment (used to calabrate equipment) . I soon found that once a year wasn't always enought to keep stuff accurate.The same for torque wrenches-micrometers and most any accurate tool.They all need to be kept calabrated to be accurate.I bougght a cheap torque wrench once to use in a hurry because the Snapon 1 was stolen.a week later we rechecked the torque on the machine -it was off.And then we compared the cheap against the good.What would u guess we found??? There is no replacement for quality ,combined with good maintauinance.