After reading this question, I understand that it is simpler to replace a space station than to repair it in order to continue its activity. All modules in a space station may not have the same lifespan (I may be mistaken, but a space station take several years to build, and is expected to be in service for about 10 years).
Moreover, it is possible to add modules to a space station. It may be possible to jettison modules as well. Given this, I imagine an old obsolete module may be dropped and then a new one may take its place in order to maintain its mission and avoid building a new space station from scratch. But I cannot find any historical records of such an operation.