By default, fade in and fade out values are inherited from the room type of the device, which means that all devices within a given room will have the same behavior.

However, as with most things in WiZ, this is highly configurable:

•  You can edit the fading time directly at device level, if you need one light in particular to behave differently.
• If you have created a group of devices, then fading can be edited within the group settings, so that the new values are immediately applied to all the devices of the group
• Finally, you can open the room settings (Home>Settings > Rooms > your room > Fading) and make changes for all the devices of the room at once

Note that the last change will overwrite previous ones. So if you have specified a special fading for a given device then make a change at room level, this special fading will be reset to the new room value you input.