What should the current practice be concerning wound drains after open incisional hernia repair?

To drain or not to drain? There is no clear evidence that using drains in patients undergoing open incisional hernia repair significantly improves patient outcomes. In some cases drains may be associated with complications and an increased length of hospital stay. Should you usually place a drain after open incisional hernia repair ? In which situations would you always drain? Which type of drain do you use?