Quote Originally Posted by DREW WILEY View Post
I keep several matched meters. When one of them reads differently anywhere over the entire scale, I sent it in to Quality Light Metric for
recalibration (about $100, but only needs to be done about once every 10 yrs).
But, if you use multiple meters, you'll need a minimum of three identical meters. If you have two, and they disagree, you have no way of knowing which is wrong. Since the odds are strongly against two meters drifting out in the same direction the same amount, three meters means when two agree and one does not, the odd one gets recalibrated.
I presume that by "several" you mean "more than two".