So, as the title says... - What is an acceptable spec? We're not talking in seconds per year or anything like that. Does anyone know a rough industry standard? - This hourmeter will be designed into a machine that will accumulate a couple thousand hours a year max. A .2% accuracy will be +/-2 hours on an accumulation of 1000 hours. Would you think this is acceptable? It sounds horrible at first because if the hourmeter were to run for a year (8736 hours) it would come up short or long by 17.5 hours. But when it comes to machine maintenence and things of this nature, I don't see a problem. Opinions are welcome. - Edit: After a bit of googling I find hourmeter specs anywhere between 20 ppm to .02%.