Why doesn't my Mac know which printer is connected?

There are three different printers on my printer menu. I connect to them via USB. Which printer depends on where I am physically. When I print a document, I always have to select the connected printer from the printers menu. My default printer is set to "Last Printer Used" but the OS doesn't seem to remember or care what that printer is. If I print a series of documents, I have to select the connected printer for each one. Am I missing something?

This has been an issue with my aluminum MacBook and now with my MacBook Air. FYI, I always upgrade to the latest versions of the OS.

Thanks for any help.

Bob Arbogast

Are any of the printers wireless? I noticed that the "The Last Printer Used" selection does not always work right when wireless printers are in use. Also if any of the printers are "all in one" printers the same thing can happen.

All wired printers connecting via USB; three printers in three different physical locations.

Two are all-in-ones. Generally the OS defaults to one of those (Canon MP970), no matter which printer is connected.

Bob Arbogast