Time is coming to introduce adult food

Chacho will be turning 1 yr next month. We've been feeding him a combination of both dry and wet kitten food and we always run out of the wet food first.   We will be having to go and get some more canned food and my question is, should I get the adult cat version of the canned food so I can start working it into his diet or should I wait.  He would still be on his dry kitten food because we still have over a half bag left so I thought I could get the adult canned and mix it with his dry kitten food and then by the time we're out of dry kitten food, he'll be a year old and we can then get the adult dry food then.

What do you think?

Is it okay for me to get the adult canned/wet food when I go to get more wet food or should I wait until he's officially a year old? 

Okay, that's exactly what I was planning on doing.  I couldn't really see buying another pack of canned kitten food when he'll be ready to start adult food in less than a month. It makes more since to just buy the adult canned and mix it with his dry kitten food until he runs out of his dry kitten food which should be at his year mark then from then on he can be on both adult