I've done a lot of painting in my life and I'd like to share a few things I've learned... you all might like it, you might not, who knows.
Decades ago, when parents and grandparents were repainting houses fairly often, paint was not nearly as high quality as it is now. There was a lot of milk based paint, as well, and thankfully, most don't bother with that kind of paint anymore... unless they are wanting retro-vintage lives, but it is hardly worth it when it comes to paint quality.
Going to "official paint stores" isn't the wrong answer, but when it comes to latex based exterior paint, it is not much different than what you get at Lowes or Home Depot. I personally don't spend the money any more. Official paint stores are more of a difference on interior paints, but still not that much of a difference. The other stores have very high quality paint now, you can see and feel the difference.
Also, no paint from any store is going to look brand new in 10 years - if you have a painted house, and you are taking care of it yourself, invest in a gas powered pressure washer, and a paint sprayer - the $200 electric paint sprayers, not the ones you need a compressor for... and get familiar with them. They are worth it.
My husband and I just finished painting our 2 story brick house ourselves, and it looks amazing. Under a thousand dollars. We just used a ladder, some flashing to shield the extra spray, and a brush to take care of runs. No scaffolding, we just took our time with the ladder. Got it done in a week.
I wish you all luck, it is not a small project.