Mom's ever said to me "Do not ever let anyone else to repeat the work you did. because it means you do not work properly and satisfactorily"
Have you ever feel like you wanna do something that anyone did ? have you ever think that you could do better than him/her/them ?
I do. But the most thing that I've ever learned is... you do have your own capacity in doing something. You could do that...and that....and that...and also that....but how much "that" become "those" that you could handle ? your capacity would determine your work quality. So make it perfect with what you could handle properly regarding your capacity.