The HP-34401A or present brand Agilent 34401A needs 1 hour to warm up for accurate measurements, but I do not have any other 6 or more digits multimeters to compare with. I do not know what I am talking about. I have an 6.5 digits multimeter and I leave it on for 15 to 30 minutes, before making a measurement and leave it on all day, until I am finished breadboarding or discrete soldering. I usually use the Fluke multimeters, which are 3.5 to 4.5 digits at most. I have a classic, the Philips PM2505 and 2518. My most oddest multimeter is the solar powered pocket sized multimeter with a self case. The Fluke 12 finally broke and I would like to trade it in at Fluke for something else. The key pad kept being non responsive for the last five years and constantly needing dis-assembly and cleaning. I would like to get the "brick," the Agilent handheld, but the economy is too slump for more instruments. The Agilent repair rate for bench multimeters are higher than Agilent DSOX oscilloscopes. Agilent oscilloscopes have a lower repair price than Agilent multimeters as listed on their Agilent web site. I do not know why? I think the lower repair rate is to have trust in Agilent oscilloscopes and increase sales to compete with low priced Rigol and Atten brands.