I made a post on another forum about L-rods and pendulums. I called them MITAS which stands for Medieval Implements of Torture And Superstition.
Of course that's a bit of a joke but I am certain that many people feel that way about them. At times I do. They are extremely difficult to learn and use. Very few people ever really learn how to use them. It takes years of practice to be good and even then there are so many distractions and obstacles. But yes, they do work if you know how and are extremely tenacious.
I've worked with L-rods for about the last thirty-five years nearly every day, usually at least one hour er day. That's a lot of hours if you add them up. I am not rich. Since I really got going with the electronic locator I have pretty much hung up my L-rods. I don't use them maybe once a month now. Don't need them and they are difficult and a big cause of stress I don't really need. Last time I tried to find my test target I missed it by a long ways. Sure, I picked up some small micron gold no doubt. I can give you many reasons why the electronic receiver is so much better, but don't care to right now.