chain
if you don't buy one the answer is never!
The 2010 Toyota Yaris has double overhead cam (DOHC).
The 2013 Toyota Yaris has double overhead cam (DOHC).
The 2012 Toyota Yaris has double overhead cam (DOHC).
The 2007 Toyota Yaris has double overhead cam (DOHC).
The 2014 Toyota Yaris has double overhead cam (DOHC).
The 2009 Toyota Yaris has double overhead cam (DOHC).
The 2011 Toyota Yaris has double overhead cam (DOHC).
The 2008 Toyota Yaris has double overhead cam (DOHC).
I have never heard of a cam belt, but a timing belt does drive the cam or cams
Does BMW320i has cam belt?