I have been using the X Series now for over three years. My key assignments mainly are sports, events & weddings. Most X shooters telling me that their camera batteries don’t last long. I went out with my friend couple weeks ago and he used four batteries in the morning before heading for lunch.
I shoot most the weekdays & weekends with my X-Pro 2 & X-T2. The events could last from couple hours all the way up to 12 hours. I do shoot with two to three bodies depending on the assignments. Having an extra third body is definitely saving my time changing the lens at the field, every second counts at the ball game.
I am fully aware a Fujifilm NP-W126 is not as good as a Nikon D4 battery in my old days but it is not as big and does not cost you CAD270. It is all about how you manage your batteries life throughout your assignments. I have lot of batteries, some are Fuji NP-W126 batteries these might be more expensive but in my experience they do last longer between charges and the life is longer than most aftermarket versions. If you are filming 4k with X-T2, I would warn you not to put the aftermarket battery into your camera body because the heat resistant capability. Even Fujifilm releases the new NP-W126s for this purpose. The best aftermarket battery I have found is Wasabi and this is my prefered aftermarket purchase. (Note: I did not get paid by Wasabi nor received any free products from them.) I ordered my first Wasabi batteries from Amazon three years ago. Couple of them having a minor issue, the battery swelling slightly that cause the difficulty to get in and out from the camera body. They are fine if you put them on the power grip. Wasabi shipped me four new replacement batteries after I reported the issue. That tells me how good they are standing behind their product.