When replacing potentiometers (pots), there are differences in shaft size you’ll need to be aware of. The shaft we are referring to is the part of the pot with threading that sticks through the guitar top or pickguard where it is held down by a threaded nut. First, there are differences between metric vs imperial shaft diameters, with metric being about 1/4” in diameter and imperial being 3/8” in diameter. In my opinion, if you have the smaller diameter shafts, it’s worth reaming out the hole to accept a 3/8” shaft. The larger diameter pots are typically higher quality in all aspects. Fortunately, you will usually only find small diameter pots on the cheapest guitars. Always use a reamer to enlarge the holes because a twist tip drill can crack the wood of the guitar top.