I am curious what camera body you use, and if you use the rear screen a lot? I am surprised how long the batteries last in my Z6II, often approaching 1000 shots before I need to swap batteries. I still bring extras everywhere I go, but I have yet to find myself in a situation where I would have been in trouble if I forgot an extra.
Use a D7200 for my dSLR.
For mirrorless an Olympus EM1-mk2 + a pro zoom (12-40/28, 40-150/2.8 or 12-100/4).
My experience with the Olympus is, for battery life, unlike a dSLR, it is not the shutter count that matters, but the 'power ON" time.
I've shot over 2,000 frames in about 1.5 hours, and still had plenty of power left.
But I've shot only about 700 frame, in about 2.5 hours, and drained the battery.
On vacation with the earlier EM1-mk1, and a non-pro lens, over several days, I was consistently getting about 4 hours of run time. It was consistent enough that I could predict when I would need to change batteries; around 11 am, and 4pm.
The next variable is the lens.
On vacation with the earlier EM1-mk1, and a non-pro lens, over several days, I was consistently getting about 4 hours of run time.
But at home, with any of the pro lenses, the run time DROPPED to less than 3 hours.
Some suspect that the AF motor in the pro lenses, suck more power than the AF motor in the non-pro lens. Which makes sense, if the pro lens AF is faster, the motor has more torque, and likely a higher peak battery drain for that torque.
I normally shoot sports at school, where the camera rarely goes to sleep.
I might power down at half-time, but other than that, it is ON.