The product my detailer used last year on my previous car and will be using on my new Stinger is called a Ceramic Nano coating. There are a number of products out there, so do your homework. But basically they performed deep cleaning, decontamination, polishing, and prep work before applying the coating. I went with the 5yr coating. I'm in a smaller metro area and didn't want to drive the 3+ hours to a large city to find someone. These guys do and did awesome work. They gave me instruction on keeping it in the best shape, etc.
What it boils down to is, if nothing touches the paint but proper car wash soap, water, and spray detailer, you'll have the best results for years to come. Obviously, if you park outside, in a dirty environment, etc., you're going to have stuff land on the car and become more difficult to remove. I was advised to just keep gently rubbing with the detailer and proper microfiber towels. So yes, spray-only washes. I try to use that as much as possible even with my wife's unprotected car. Otherwise, I'll use the manual wash bay and use their brush after rinsing it out as much as possible, trying to apply as little pressure as possible to get the job done.
I'm no expert and often am lazy about my homework on a topic. Car paint and finish care is almost a religious thing. So you find those who promote what they believe to be "the best" everywhere, with lots of variations. I didn't have a lot of choices, but have been very happy NOT having a multi-function shop do the work and getting someone who uses professional products, has the facilities and tools, even if it's a part-time thing for them.
Hope this helps!