There is a law in the torah (and the meforshiim afterwards) to attach tzitzit to all four cornered garments that you will wear.
Ok. I understand that.
But where did it come to pass that some people say one is required to wear tzitzit?
If I am not wearing a four corned garment, why should I go out of my way to acquire one?
Is it a halachic obligation to? or is this just custom?