We often work on R&D projects that evolve in time using the same literature review and the same materials and methods; yet, when we publish our incrementally progressing work we have to repeat certain background information within the new article so as the reader wont have to be referred to older texts.
Today, peer reviewed journals and conferences are utilizing anti-plagiarism software (e.g. iThenticate) to counterfeit against plagiarized material - one of which is self plagiarism.
In your professional opinion, to what extent should self-plagiarism be tolerated?