It is generally courtesy to use the plural 'we' or 'our' in papers, even when the primary author was the only contributor. While using personal pronouns in academic papers is typically a very bad idea, I have seen them being used in theses. What gives? Technically a PhD thesis is only meant to be the candidate's work, but if this work features previously published work surely you'd expect to same rules to apply to the thesis as applied to the academic papers?
So in terms of professional appearance and etiquette what is the (typically) correct approach? Should personal pronouns be used in a thesis?