I am used to the metric system where everything is simple and consistent. I can do quick conversions between metric and imperial in my head, but especially when it comes to volumetric measures, I cannot be sure if British or US Customary units are used. Here I refer to units such as gallons, pints, etc. not cubic-linear units.
Questions arising from this confusion is how to know which unit is being used.
In technical publications, will the author or publisher note the applicable units somewhere?
For everyday use, is there a convention that says U.S. gallons or otherwise must be specified, or is it up to the whims of the manufacturer? If not, how can I reduce my chances of making an error if I cannot ask or measure?