How many months minimum should you work with a client?

It’s been 6 months since i worked with my first client as a medical VA under purple agency. They trained me to be all-around which Im grateful for and have been nice to me, but I plan on looking for a direct client or move to an agency that offers better compensation and benefits.

Im not going to leave now/right away just yet, but just sharing this for future notes.

How long do you think is enough to work with a client before moving to the next? Do you have tips on how to break it to your current client that you plan to leave soon? I want to end my service with them on a good note.

EDIT: Thank you so much for the advice!!! I agree na super saturated talaga field natin. Ill for sure upskill myself and I gain some more confidence while im with my client :)