Patio lights make the most sense for anyone with an outdoor space they actually use after dark, a porch, a deck, a scrap of garden with a table on it. If your idea of outside time is dashing to the car, you can skip this entirely and spend the money on something that'll get looked at more than twice a year.
If you own none, start simple with a single warm toned strand, nothing with a pattern or a flicker setting, just plain bulbs on a cord you can run along a railing or between two posts. That one strand will tell you more about how you actually use the space than any plan drawn up in your head. Where it falls apart is mixing too many light temperatures at once, a warm strand next to a cold white spotlight next to a solar stake that's gone that sickly blue, and suddenly your patio looks like a parking lot that's trying too hard. Pick one tone and stay loyal to it. Also be honest about exposure. A light rated for a covered porch is not the same as one that can take a Carolina thunderstorm sideways, and I've watched a string go dark after one bad weekend because someone trusted a rating that was more marketing than promise.
The difference between a strand that lasts and one that's junk by next summer comes down to things you can check with your hands before you ever plug it in. Feel the cord itself, it should be thick and rubbery, not thin and brittle like it'll crack the first cold morning. Check the sockets, good ones are sealed where the bulb meets the housing, bad ones have a gap you can see light through, which is also a gap water will find. Give the whole strand a gentle pull at a few joints, nothing should wiggle loose. And look at how the bulbs are set, proper glass with a visible filament look will age fine, cheap plastic ones go cloudy and yellow within a season and start looking like something off a fishing boat. A few dollars more at the start almost always buys you another two or three years outside, which is a better trade than most people think when they're standing in the aisle trying to get it over with.
What makes one worth having, though, is smaller than all that. It's the warm wash it throws across a table at nine at night, soft enough that nobody's squinting, steady enough that you forget it's even electric, just a bit of evening that stays lit as long as you want to sit out there.