For me it all depends. If it is a strip with no intersecting piecing I will rip ala Ricky Tims method. I have done that with little bits and long strips, also no bias. If the ripping is fussy (like I inserted a unit the wrong way or involves bias) I will either use my seam ripper and do every four or five stitches on one side and remove or I may take my rotary cutter and pull the seam to show the thread and carefully nick away at it like NativeTexan describes. I have accidentally cut into fabric too many times when I try to do like Rob describes.