Do Alerts have a shelf life?

My appearances here have been short and infrequent lately, so maybe this is just something I haven't come across before. When I checked my Alerts, I had only one from yesterday. I clicked on "Show All" and still had just that one. I know that I should have some Alerts in the last couple of months. Did something change, or am I not holding my mouth right? **

** NOTE: I'm keeping the possibility that I'm just a dumbass in reserve.

 

Using "show all", the last alert I had was July 10th. However, alerts (likes in this case) from July 8th are not there, Don't know if I had any "quoted you" on July 9th.

So definitely 15 days, with a "maybe" for 16 days.

EDIT: Still showing July 10 alerts,
Thus, alerts have a 16 day shelf life.

 

Thanks, Takao. That pretty much answers my question.