If I have understood correctly, most people doing their PhDs do their best to avoid any teaching duties while in their programs. However, I think I might want to do some teaching too. Of course, I have a hidden agenda. I would hope that:
Usually, (good) skill to teach is required later on your career, when applying for tenured positions. I would receive good experience.
Giving lectures related to my research topic might get someone interested about it. I could delegate some minor (boring :-) part of my research topic for someone to do as his/her master thesis.
Am I hoping too much here? Any experiences?