There aren't enough hours in the day to answer all of DS's questions. He'll turn three later this month.
We did find something that helps. DS doesn't get to ask "why?" The only response that gets from us is "Why what?" If he wants an answer, he needs to ask a complete question. We've found that a lot of the time, why is just his way of saying he wants more conversation. Getting him to refine his questions makes him a better thinker, and a lot less irritating!
Me: We're going to the dentist.
DS: Why?
Me: Why what?
DS: Why are we going to the dentist?
Me: We're going to the dentist because I need to get my teeth cleaned.
DS: Why?
Me: Why what?
DS: Why... How will he clean your teeth?
We did find something that helps. DS doesn't get to ask "why?" The only response that gets from us is "Why what?" If he wants an answer, he needs to ask a complete question. We've found that a lot of the time, why is just his way of saying he wants more conversation. Getting him to refine his questions makes him a better thinker, and a lot less irritating!
Me: We're going to the dentist.
DS: Why?
Me: Why what?
DS: Why are we going to the dentist?
Me: We're going to the dentist because I need to get my teeth cleaned.
DS: Why?
Me: Why what?
DS: Why... How will he clean your teeth?










, albeit tiring some days, 

)