During various projects, I needed to make sure that the use case model I developed during the analysis phase is covering the requirements of the project. For that, I was able to have some degree of traceability between requirement statements (uniquely identified) and use cases (also uniquely identified). In some cases, enabling traceability implied some additional effort that I considered (and later proved) to be a good investment.

Now, the biggest problem I faced was to maintain this traceability later, when things started to change (as a result of change requests, or as a result of use case changes).

Any ideas of best practices for traceability maintenance?

(It can apply to other items in the project - e.g. use cases and test cases, or requirements and acceptance test cases)

Later edit Tools might help, but they can't detect gaps or errors in traceability. Navigation... maybe, but no warranty that the traceability is up-to-date or correct after applying the changes.