most of the time from what I have seen and known is that it is dependent on the spell.. I have done this really big protection spell before that needed both mine and my uncles power. I also know that it may also be on how strong your power is.. if you are not strong enough for the spell than you may need another..
Re: a question about spells By: ARVY2 Jun 24, 2013
Post # 6
both anwer is correct. In addition, the reason why, because of the desire to make the spell to work, some people know that if they cast or chant a spell it will work, even how many times you cast a spell without determing your goal, without the proper pronounciation, without focus, strong desire, visualization, and faith. It probably wont work.
go here to learn how to cast a spell: