If you have the G9II (which I think is an amazing camera) do the software update now. The camera is live the moment you switch the camera on. For those of us who never turned our camera off when birding due to the agonizing startup speed the wait is over. Now if you are taking a break or walking to a new spot and you need or want to save battery power, don't fear startup is amazing.
Good job Panasonic.
Note that this is only true if you've powered on the camera recently. At a certain point it goes into a deeper sleep and takes the same amount of time it used to - around 5 seconds. This is my experience with the new firmware with the S5 II, at least.
Do you have an idea on the length of time it needs to be off to experience the deep sleep / slower start up?
Mine has never seemed slow to start up - I use it most days weather permitting and it's rare that I might leave it off for more than two days - I have never "noticed" a slow startup, but am not looking for it either... The vf seems to be active in 2-3 seconds.