Stretching too far, especially around an edge to create an overlap, may cause problems down the road. If you encounter some areas where the vinyl is peeling back, the likely culprit is because the material was spread too far. Lifting and separation occur because the vinyl has internal memory, just like a piece of elastic. It will always attempt to return to its original state once stretched.
The truth is, the vinyl's internal memory can be destroyed and reset when heated and stretched within acceptable limits. You can tell you're pulling too far because it causes the print to thin out, turning the color white the farther you go. It also looses tactile strength in the adhesive because the piece is covering more surface area than it was intended for.