What is the importance of postdoctoral teaching experience for US tenure-track jobs? I'm a math Ph.D student in the US who has just accepted a four year postdoc--NSF postdoc at a US school interrupted by a year in Europe. For better or for worse, I am only slated to teach for two semesters in those four years--likely during the second semester of my 3rd year and 1st semester of my 4th. 

I am planning to apply for tenure track positions in the US afterwards and am wondering whether the relative lack of teaching as a postdoc will adversely affect my application. 

Should I be looking for volunteer teaching opportunities? 

If it matters as a graduate student I had fairly extensive teaching experience, serving as sole instructor for courses in various levels of calculus, multi-variable calculus, and linear algebra for four years in addition to mentoring REU students and grading/TA-ing graduate and advanced undergraduate courses.
Two semesters of teaching in four years sounds almost ideal for a postdoc, so I would not be worried about that -- if you are aspiring to be a mathemagician rather than teaching-focused mathematician.