I am lucky to receive a steady supply of requests to talk, write references, conduct reviews, undertake research degree examinations, and be an external examiner. Unfortunately due to pressures on time I am only able to agree to a limited number of these, and only when the focus strongly overlaps my own interests.
For reference requests, if you would like me to write a reference for you, please discuss with me in advance. I put a lot of work into writing references, and in general I am only able to agree to write references for those whose work I know intimately, or whose research area strongly overlaps with my own. University reference requirements are often too complex to navigate otherwise.