I\'m working on some sort of online multiuser editor / coop interface, which will be doing a lot (as in, thousands) of ajax requests during one page lifetime.
What w
Create a new one when you need one. The GC will deal with the old ones once they are not needed anymore.
However, for something like a cooperative editor you might want to consider using WebSockets instead of sending requests all the time. The overhead of a small HTTP request is huge while there is almost no overhead with a WebSocket connection.