You can expect to write software with a long (10+ years) shelf life in astronomy. Especially if you write observatory infrastructure code. Things like data-flow

You can expect to write software with a long (10+ years) shelf life in astronomy. Especially if you write observatory infrastructure code. Things like data-flow software, science archive code, pipelines etc. Also most end-user analysis software tends to stick around for a long time: in some cases 20+ years, which of course is good and bad.