A great teacher knows his/her scope of mastery. So what happens if your pupil is great already? Should you hold on? Or tell your student you have to move on. Then tell them get another teacher that would take you on a different perspective in your field.
Yes you should do it, it would be selfish to take it all for yourself. I see this reality that they want to Take credit on everything for that pupil. If you are one of them then I’m sorry your not really helping them anymore. You’re not allowing them to grow and reach the full potential. Maybe you are jealous of the potential. By not letting them go, you feel more superior. Please don’t be that teacher.
Explaining this aspect might offend your pupil, so explain it carefully and make it a point that it’s for his/her growth. I always tell them you eat pasta as your fave but on a daily basis it would be another story. Explaining to them that they’ll gain a bigger picture in life for their passion. You may have some clingy ones,Hahahah. On those situations I tell them that it took me a few teachers, lots of masterclasses and learning different things made me who I am today. So if you think they are ready,then set them free.