Most every agent I know has provided some kind of help or assistance to a client after escrow has closed. I don't just mean giving an after-closing gift, although that is certainly a nice and often beneficial thing to do. Rather, I refer to providing some service in connection with what might be called the aftermath of the transaction, such as tracking down the association pool keys, arranging for a cleaning service , helping to move the piano, following up with the closing agent over a mistaken charge, or calling the roofer about some broken tiles. The list could go on and on.
Some after-closing assistance involves a lot of effort. Some only a little. Most agents - though certainly not all - are happy to provide it. Service like that cements relationships, enhances the agent's reputation, and may often lead to referrals.
Sometimes agents may receive requests for after-closing assistance some period of time after the transaction is finished. This is not uncommon when it comes to items that might be covered by a home warranty policy. Three months after escrow the dishwasher goes out. You get the call: "Is this covered? What am I supposed to do now? I know I had a policy included with the closing papers; but I don't know where they are."
In our part of California we are likely not to see significant rain from May to November. (And by other state's standards, not even then.) Thus, experienced agents here are not surprised to receive a "my-roof-leaks" call up to five or six months after a sale has closed.
In most of these assistance situations it is generally understood that the agent's rendering of help is voluntary. They do not have an obligation to be of assistance. It is not what they were paid for. To be sure, there are not clear, bright lines here. A buyer might think it is part of his agent's job to obtain a garage door opener if the seller didn't leave one on the kitchen counter as promised.
On the other hand, few would think it a breach of duty if the agent didn't help him fix a sprinkler that was broken during the move-out/move-in period.
It is important for agents - and probably for principals too - to understand that it is a well-established principle of law that an agency relationship terminates when the purpose of the agency has been accomplished. In general, then, agents of either buyers or sellers are no longer agents once the closing has taken place.
(As I said, there may not be an entirely bright line here. I can imagine the argument that the purpose of the agency was to buy the home with the pool keys.)
Some real estate professionals talk about wanting to be "your agent for life." They probably don't really mean that. They don't want to be someone's fiduciary for life. They don't want to have a constant duty to put another person's interests above theirs. Rather, what they want is that when someone needs an agent, that person will call upon them.
Many real estate agents provide a lot of help to their principals both during and following a transaction. The former is often, though not always, a matter of duty; the latter is seldom so.