title: does angularjs $watch every property on a $scope or only those referenced in template?
body: <p>Since all watches are evaluated on every $digest, keeping their number low is a good perf practice. To rephrase the question title, is there a perf penalty for declaring either a variable or method on $scope inside a controller, when those aren't being referenced by related template (if there is a penalty one could declare those as local variable on controller object instead).</p>