I don't know about anyone else, but I calibrated all my braid and mono line counters. I don't bother with my leadcores even though they have counters. Wire divers I didn't bother as that's too much of a pain with the wire. If I found one that was out by 40 feet I think I'd relegate it to the downrigger rods. I have 8 mono or braid counters and not one of them has been out more than a few feet on the first 100 foot. accuracy drops the more line out but 40 feet out would drive me nuts.