Safeguards should be provided to protect end-users against unsolicited communications for direct marketing purposes, which intrude into the private life of end-users. The degree of privacy intrusion and nuisance is considered relatively similar independently of the wide range of technologies and channels used to conduct these electronic communications, whether using automated calling and communication systems, instant messaging applications, emails, SMS, MMS, Bluetooth, etc. It is therefore justified to require that consent of the end-user is obtained before commercial electronic communications for direct marketing purposes are sent to end-users in order to effectively protect individuals against the intrusion into their private life as well as the legitimate interest of legal persons. Legal certainty and the need to ensure that the rules protecting against unsolicited electronic communications remain future-proof justify the need to define a single set of rules that do not vary according to the technology used to convey these unsolicited communications, while at the same time guaranteeing an equivalent level of protection for all citizens throughout the Union. However, it is reasonable to allow the use of e-mail contact details within the context of an existing customer relationship for the offering of similar products or services. Such possibility should only apply to the same company that has obtained the electronic contact details in accordance with Regulation (EU) 2016/679.