Accuracy of details such as dates, numbers and people is sensitive to change so it is important to check when sources were published and whether details are up to date.
Gall cywirdeb manylion fel dyddiadau, niferoedd a phobl fod yn agored i newid ac felly mae'n bwysig cadarnhau pryd y cyhoeddwyd ffynonellau a ph'un a yw'r manylion yn gyfredol.