They ought to. Solar panels themselves degrade with time, but in this context that should just mean they take a bit longer to charge (maybe 20% to 30% after 8 years).
I have an emergency jumper battery with a cigarette lighter hole. I bought it after leaving the lights on in my Jeep while I was in class. I haven’t had to use it for the Jeep battery since then but I keep it fully charged at all times just in case. I can use it to charge anything that plugs into a cigarette lighter or into the converter thingie that I bought from EMS (USB). So, we can charge both or personal phones and his work phone.
Never had to though. We only lost power for 4 hours. When we lost it for 3 days last Halloween, we used our phones one at a time and that got us through.
I have one that has a regular outlet on it as well. It can be recharged both through an outlet and car lighter port. We take it along camping and those darn kids charge their phones many times. Some you can buy are pretty big, but even mine can run a few low wattage lamps and radio at the same time. It lets out a little alarm if you try to draw too much power at once.
wait, what?
The vast majority of public bathrooms have to be cleaned very often, and that involves–ta!DA!–outlets.
Find a building with power and a public bathroom. I used my local ShopRite.
That’s an odd suggestion because a) it’s stealing, b) places close by would also likely not have power, and c) it involves hanging out in a public washroom for an hour while your phone charges.
Wow, my main reason to have a gas heater is to be able to use it in a power outage - reliability in case either source fails is also the main reason given by buyers of dual cookstoves in Spain (the kind where some fires are gas and some are electric).
For the phone or a laptop, car chargers are an option; there’s also manual power generators (just a dynamo you power by hand), but at the rate some phones eat power, one of these would count as serious exercise. If you expect to need to charge anything reliably, a solar charger is much better than the little dynamos.
Mind you: the car charger requires a working lighter socket. My car used to be a rental, so the socket got disabled (given how many smokers I know who are missing a light more often than they’re out of cigarettes, I can see the logic); the dealership didn’t re-able it and I haven’t bothered.
Power was out, and I had a hurricane lamp but no matches. I went around the corner to a bar that was officially closed, but there were still people cleaning things up the best they could. I asked for matches, and was directed to the bar where there was a book or two of matches. I thanked them, went home, and lit up my hurricane lamp.
Car charger is a very good start and puts you way ahead of the game.