The only standardized 12v sockets are cigarette lighter sockets, and they suck @$$. As a dealer tech I had to replace cigarette lighter fuses all the time from people putting plugs in and then turning them, shorting the socket. On a side note, always put your lighter-style plugs straight in and straight out.
I'll agree the socket design on most seem to be pretty crappy.. however, in my life I've never blown the lighter socket fuse plugging anything in (other than a shorted-out phone charger cord.) Guess I'm just lucky? I've dealt with numerous lighter sockets that were worn out and made bad contact, and had to twist the plug of whatever I'm hooking up - spinning it around until it makes a good connection. I've tried cleaning them with DeOxit with mixed results. There's got to be some effective means of cleaning them but I don't want to use anything abrasive that will scratch the contacts and promote corrosion. Maybe I just need to dig in there with a good ol' #2 pencil with a good eraser tip on it (with the lighter socket fuse pulled, of course.)
Here's a scenario where the USB sockets wouldn't help me. This is a Streamlight flashlight charger, and my wireless tow light charger, plugged in on the SS. On this occasion I probably had my phone charger plugged into the socket on the rear of the console. (Console-mount Moon Pie needs no charging.)
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This setup would be a pain on the '93 with only one socket. I don't dig those plug-in multiple outlet gadgets, either. Bulky and usually very low quality.
Richard