Hit 500 rail spikes forged and my hammer grip finally clicked

I've been forging rail spikes into hooks and bottle openers for about a year now. Last Saturday I finished number 500 and noticed something odd: my left hand stopped cramping around halfway through the day. I used to white-knuckle the hammer whenever the steel got too hot or the shape came out uneven. Turns out all that repetition taught me to let the hammer do the work and just guide the swing. I counted back in my journal and the change started somewhere around spike 430, so it took that many tries to build the muscle memory. Has anyone else hit a random count and realized their technique shifted without them noticing?