The first common mistake that people make is cutting the part off of the vehicle before the service part arrives. This may not sound like a big mistake, but if you cut the original part in a location that the service part will not reach, you may have to order another part all together to fix the mistake.

This also leads into looking up the service information before cutting either part. Just because a part is typically sectioned in say, the sail panel area of the quarter panel does not mean that every car is that way. Many vehicles have hidden reinforcements and/or composite reinforcements. This means that many of the traditional locations to section a part are no longer possible or are being done in a location that is unique to that specific model. If these reinforcements are damaged, they typically will require replacement at a factory seam. This can lead into a much more intrusive repair.

Both of these repairs can lead to an extended cycle time due to additional part orders. Before making any cuts, make sure you have identified the correct cut location and any materials that could be hidden behind the panel.

Additional I-CAR Collision Repair News you may find helpful:
What's The Difference Between Sectioning And Partial Replacement?