EggTimer is a counter that runs as soon as it is started.
The Start condition does NOT have to remain True in order to keep counting.
Once Start is activated it will run the count.
If the Frames are set to 0 it will output a Reached True immediately, but Running will always report False.
If the Frames are greater than 0 it will output a Running as True while the EggTimer is running.
If AlwaysTrue is connected to the Start input, the EggTimer will start counting as soon as a particle enters the assigned group.
This way it's super easy to let particles switch back and forth between groups in set intervals. Check out the sample image: switch groups example