DFU's are Double Follicular Units. We know each follicular unit can have 1 to 4 hairs. DFU's are utilized when patients have a lot of 1 and 2 hair grafts and are short on 3 and 4 follicular units. We wouldn't use DFU's on someone who has an abundance of 3 and 4 hair grafts. We make sure DFU's are cut to a certain size - typically they consist of 2+2 fu's or 2+3 fu's. 3 fu's or 4 fu's are not kept together as these DFU's would be too big. You could keep individual FU's and plant them close together but you can't make the incisions any closer than what occurs in nature. The DFU's provide more density on the top of the head where density is needed.
You may ask if it looks pluggy.......the short answer is no. The grafts are more in a line. We've used DFU's for years and have never seen them look pluggy.