14/3 works for nearly all outdoor lighting.

Yes. For most outdoor lighting setups — string lights, path lights, low-voltage stuff — 14/3 is more than enough. It’s rated for 15 amps, and even a long string of those Edison bulbs pulls maybe 3-4 amps total.

The only reason to go up to 12/3 is if you have a very long run (over 100 feet) or you’re running high-wattage flood