By reset the odometer, I meant when you change batteries, can you set it to the old number (if you remembered to write it down) instead of zero. My wired one, you can't, but I suspect some you can.

My wireless receiver would burn through batteries a lot faster if it was always on waiting for the wheel to turn. Mine, after you are stopped for 30 minutes, it shuts off the radio receiver. So, that is why they are not instant on. If I am riding solo, I remember to start it, but when I am riding with people, I am often distracted and forget to wake it up when I start out after lunch or something like that.

My wireless ones, when the wheel is turning, the sender (part on the fork) has a light that will turn on for about a second, every few seconds. And when that light comes on, that is when the data on the receiver screen changes. Thus, I assume that when the light is on, that is when it is sending info to the receiver. Because of that I think sometimes the number of wheel revolutions is not measured with sufficient accuracy which causes the error. In my case the error is usually over estimating distance, not under. If it was underestimating, then it is possible that the receiver on the handlebar did not receive the data sent by the sender on the fork occasionally.

My rando bike is the only computer where I really want to make sure I have very accurate distance, I use an old wired one there because it seems to be spot on.