[ClockFace + Layout] Custom clock: battery drain

Calling this.layout.update(); every minute might be expensive?

You could try removing lazy rendering, and do something like this:

if (changed.d) { // check days first: may need to update layout
      this.layout.update(); // dayStr could be a different size now
      this.layout.render(this.layout.date);
      this.layout.render(this.layout.dayStr);
}
if (changed.h) this.layout.render(this.layout.hour);
if (changed.m) {
      this.layout.render(this.layout.minutes);­
      this.layout.render(this.layout.steps);
}