How do I keep my translations from going "stale" and disappearing when my web application is rarely used?

Hi, we have a web application that is used only during an annual process, so it gets accessed only for a couple months of the year and then it's fairly unused the rest of the time. We made a separate version for France (in French) and for Mexico (in Spanish). When people access these sites after several months, it seems like all the translations are gone and we need to go through this process again where we click all over the system and phrases get "pending" in Localize, and we need to approve, etc. Why does this happen? Is there any way to turn this feature off so our translations will "stick" all year long?