This little scale has stayed calibrated for 6 months. I have a 500g and a 1000g calibration weight. I calibrated the scale the first time I used it, and it has stayed dead on every time I reweigh the calibration weights.
I deducted one star though for a frustrating 'feature': the ridiculously aggressive auto shut-off engages after being idle for 45 seconds! Just about every time I reach over to put the next item on the scale, I have to turn it back on first. VERY irritating. It should be at LEAST 3 mins, and I think 5mins would be reasonable. Exactly how much 'juice' does the scale use sitting idle anyway? Can't be MUCH!?