Is there a recommended maximum number of transactions any one address should ever receive? The pool I am with has sent about twenty transactions to one address I gave as a 'send to' addy. Could this one address just go on and on taking more and more of these transactions? A hundred of them? Ten thousand?
You can use it as many times as you like. There is no upper limit.

The reason that people advocate using new addresses is that it increases anonymity. For example, people who know your address can easily look up how much has been sent to it in total. See these questions for some more info on anonymity:


How anonymous are Bitcoin transactions?
How can one remain relatively anonymous while using Bitcoin?