# Maintenance burden Maps intended for ongoing use often require a commitment of resources and tools and so can be quite costly to maintain. Maintenance may be required whenever there is a change to the source or target code sets. Some terminologies are more dynamic than others, with a faster update cycle which can increase the maintenance burden - for example Medication releases can be monthly, whereas some classifications have only a two yearly cycle. The more dynamic the code sets, the greater the maintenance burden. During maintenance, the following should be considered: * for new source codes, new map rows need to be created * for retired/removed source codes, map rows need to be removed * for retired/removed target codes of maps, map rows need to be updated to find suitable targets * for non-equivalent maps, map targets should be re-evaluated to check if there is a more suitable target Maintenance can be non-trivial and consideration needs to be undertaken before beginning the mapping process on whether it is worthwhile developing, implementing and maintaining a map or whether a different implementation pathway is more appropriate. Provide Feedback --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-mapping-guide/evaluating-mapping-as-a-solution/4.2-maintenance-burden.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.