You can certainly experiment with other coils if you'd like and the Melo III does accept a ton of different coils. However if you are happy with the vape with your preferred coil, there's certainly no reason not to get more. You can vape them, and if you wish, begin experimenting with different coils, but if you have a coil you enjoy, you can certainly stick with it, AS you experiment with different coils and see if any of the others may work well for you.
Anna