How many positions do you have? Seriously, how many do you have? It's tough to navigate asking current staff if they plan to search or if they are staying. Are there HR policies or existing contracts that dictate the depth of this conversation?
If your organizational culture supports it, have an “intent to stay” conversation and even create a form to document it. The intent is not to push anyone from their position, but your ability to properly function and search within the traditional window for the following academic year is also important. If you are able to follow this process every year, it helps prepare current staff for their own search process, making sure they do not leave it all for the last minute and experience an unsuccessful search.