If you're like me and have several guitars, you may not remember what gauge strings are on each guitar. Also, when acquiring a used guitar, you might need to find what's on it. I try to remember to put something from the string package in the case compartment, but with the environmentally friendly multiple packaging, and my tendency to forget to do this, I've used a micrometer to check gauges for years. I've got a basic Starret micrometer that I've had for at least 30 years, but as I've gotten older and have developed some vision issues, the always hard to read barrel marking have gotten impossible to read without a magnifier, so I bought an inexpensive digital readout from iGaging. Lots of upside for casual users. Zero set is automatic, just press and hold a button. Readout is clear enough that Mr. Magoo might be able to read it. A nice touch is the little "S" shaped screwdriver that fits the battery cover exactly, no more need to find a dime or something to open the battery compartment. If you would use it for more operations, there is an adapter for using blue tooth to input data into a spreadsheet. Only downside for me, so far, is the case is bigger than my old one's, so won't fit into my guitar tool box as easily.