Been using one for years because adjusting RPM by ear is about as accurate and tightening a bolt to torque value by feel. Go for it.I do my own lawn equipment motor repairs myself. So lately I have been thinking and it would be good for me to have a good means to check the rpms on some of this equipment. I know I can buy an Ebay or amazon tach that you wrap the pickup around the plug wire but not sure if this is the correct way to go. So, question is what do you real world repair people use? If you all feel that the inexpensive ones are good enough than I would go that way, they just seem to be hokey. Because of having 2 and 4 cycle plus single to twin cylinders the inexpensive ones you have to keep changing the info to get the proper rpm readings. I don't think I would need to spend $300.00 to get something that would work for my use. Thanks Maybe I am just over thinking this.