I used to GB mine righteously a few times a hunt, but for the past 3 months I haven't and I haven't noticed a difference. The only thing that I may have noticed is it may bring the readings in more accurately, but I am not totally sure of this because there are some places that even when I GB the readings would be a few numbers off (e.g. pennies will read 12.40-12.41 instead of 12.42-12.43)
With my Deus if I didn't GB most places at least 3 times I would notice a lot of falsing and the numbers would be off 5-8 points. Seems the CTX is very stable and may be tracking.