A mailing list using VERP, on the other hand, must send the entire message body repeatedly, which leads to an overall increase in bandwidth usage. This inefficiency is usually not considered a big problem, especially by qmail users, since qmail always sends messages once per recipient, even when VERP is not being used. Some packages mitigate the impact of VERP by applying it selectively, for example a mailing list manager might only use VERP on 1 in 10 mailings. This way you can gain much of VERP's tight bounce control and accurate feedback without incurring the processing and network overhead every time.