I take Google alerts. In October of last year, I discovered a deficiency in the process.
To get a more balanced view of a two week old story I was reading, I clicked the “see all stories on this topic” link. By experimentation (I had two alerts from Oct 29, as well as one alert each, from Oct 30 and Oct 31,) I am able to discover with some confidence that news stories older than 2 days old are no longer linked.
I haven’t thought of an ordinary reason for this, but whether or no, it’s a good idea to know that context (for old stories) might not be available.
Washington Post and Reuters make it a practice to withdraw links over 10 days old, in order to monetize queries.