Author here, 10 years later -- I agree. I'd remove that rule wholesale in an update of this guide. Unsigned integer types can and should be used, especially for

Author here, 10 years later -- I agree. I'd remove that rule wholesale in an update of this guide. Unsigned integer types can and should be used, especially for memory sizes. I would still advocate for large signed types over unsigned types for most domain-level measurements. Even if you think you "can't" have a negative balance or distance field, use a signed integer type so that underflows are more correct. Although validating bounds would be strictly better, in many large contexts you can't tie validation to the representation, such as across most isolation boundaries (IPC, network, ...). For example, you see signed integer types much more often in service APIs and IDLs, and I think that's usually the right call.