I love open-source software. Thanks to Marcello Mamino's Tg timegrapher, you can enjoy using your favorite computer and soundcard to help maintain your automatic watch's accuracy or to diagnose and determine if service is needed.
I'm an amateur, but I like professional tools, and this software, which runs on everything from a small Raspberry Pi to machine powered by the Beast of Redmond, presents an inside view of your watch's movement - it's not an x-ray, but a sophisticated sound analysis!
Here we see a Seiko SRP615, which uses a 4R36 movement:
You can download and build the client from source, install binaries, or as I did, install non-native binaries and run the client in emulation under CrossOver for the Mac.
The first task is to 'calibrate' the software to your soundcard. Clamp a quartz watch onto your input mic (I used a Logitech webcam), then click the Calibrate button. Let Tg collect data and it will eventually display an offset value to use when running an analysis of your automatic watch. You'll want to make sure that the input sound is 'clean' (represented on the bottom line of the picture) so you'll get best results, but Tg is pretty robust - it will work!
You can use the 's/d' values to determine if your watch is running too slow or too fast. You'll want to see the differences between these values with the watch in different positions (dial up/down, crown up/down, etc.) Then crack your caseback, adjust, and check again. This can save a lot of time instead of doing the adjustment, then letting the watch run for two days or so.
Have fun, and thanks, Marcello!
btw, it also appears that my manual regulation efforts, conducted before trying this software, were pretty successful with my skx007: