It's not down for an oil change at all, same with the rear diff', just check and top up at each service.
For what it costs for the oil, and how easy it is, it's worth changing it to flush any metal particles out.
Just make sure you undo the filler plug first, before the drain plug. Can but a bit difficult if the filler plug's rounded off, or soon will be if it's too tight. It's a shallow nut.
