The same advise applies whether you are selecting your examples for use at interview or for use when completing your application form (required for most public sector interviews). Where possible, lead with your most recent work examples. Only use a non-work example when you have no other example that you can draw on to illustrate your competence.
After selecting your examples, you then need to remind yourself of the detail of those work tasks or projects and what you accomplished. The level of detail you provide is very important. Keep the focus on the aspects of the work that demonstrate the competency.