Do you take recurring blackout warnings seriously?

I would separate the warning from the basic risk. A specific prediction that a blackout is imminent is not much to go on, but local outages do happen. Keeping enough water, shelf-stable food, a flashlight, batteries, and necessary medication for a few days is useful without assuming a major crisis is coming.

After several years of alarming predictions that did not happen, I would be wary of treating another one as evidence. Ask who is making the claim and whether they give a verifiable reason, a location, and a time frame. If those details are missing, it is probably not a sound basis for expensive purchases.

Preparedness does not have to mean stockpiling for months. Think through what stops working when your power is out: phone charging, heating or cooling, cooking, and any powered medical equipment. A modest plan for your household and a way to get reliable local updates will do more than chasing every dramatic forecast.