I was not affected by the blackout.
But I'd like to make some points about preparedness and runtime IF you don't carry spare lights and/or batteries with you.
Regardless of how many hours your light(s) will run on a FRESH battery, just be sure that you don't forget that what really counts is how much time is LEFT on the battery when you need it. A light with a 10 hour runtime may become useless if it's in the final 15 minutes of battery life and you need more than that. This is especially true of current-regulated lights which won't dim (and alert you) until the very end. You don't know how long you'll need light, so err on the generous side. I don't usually carry spare batteries on me, unless I am specifically anticipating long usage, so instead I check and change them when they get below a certain voltage. I don't like to waste battery power either, so these partially used batteries go into less critical devices or ones that I use at home or car where I DO keep spares. If you do carry spares WITH you, all the better.
For incandescent lights, an extra bulb is a neccessity.
In addition to battery life management (or at least instead of) it is also wise to carry more than one light, since this increases the amount of light-time you have and because even good quality lights can fail. With most CPFers that need not be said, but if you are a minimalist and insist on only one light, at least carry a tiny keychain light as backup. I personally 24/7 carry the ARC-AAA and additionally EDC the ARC-LS and Photon II yellow. Additional lights are available in car and home.
Your EDC or 24/7 or bug-out-bag gear should be maintained in top condition in anticipation of emergencies. Keep cell phone charged, supplies refilled, lights and other gear in good condition, etc. Have backups for critical gear. Get to know how to use EVERY piece of gear beforehand. You might not have time to figure it out later. It will give you confidence and reduce worry when difficulties arise. Take care of your gear and it will take care of you.
Hope for the best, prepare for the worst.