Anyone conducting genealogical research should make use of a research log, every time they research. Logs are not only for professional researchers. They should be used wherever research takes place, whether at home or at a repository.
Logs should be implemented even when "nothing" new is located in the course of research. Firstly, knowing when and where research has already been conducted is important. This avoids wasted time due to repeated searches. Secondly, negative evidence can be just as useful as evidence.
A research log should contain specific pieces of information. Firstly, the date and possibly also the time should be recorded. Secondly, the location of the source you are consulting should be recorded. It is helpful to include the repository name, address, phone number and website. That way, if you ever need to refer back, you know exactly how to do so.
Thirdly, a citation should be created. Next, record exactly what information or evidence is being searched for. Finally, record the findings or evidence that has (or has not) been located.
If you need a research log document or help creating your own, please reach out.