I have learned so much about skincare from this very forum and the wise people therein through the years and highly recommend a good read by putting suitable words in the search bar at the top. Personally I have gone backward in my approach to skin care nased on my own budget. I went straight for the expensive brands, Decleor and Elemis (gave Liz Earle and lots of other brands a try but wasn't impressed) and have slowly wound backwards and have just started using Aldi serums and creams and am very happy. I still have a lot left of Elemis which now cost a fortune, I cannot believe the prices they are charging now. A tri enzyme kit I paid £50 for two pieces a few years ago would now cost over £194 at Elemis's own site, that is crazy and I would never pay that nowdays. And to be frank, the difference in price compared to standard products that cost 10 times less is NOT 10 times inferior, there is a soom difference no doubt but no where near worth what these other expensive brands THINK they are worth. So don't feel you are missing out on anything.
I am so cynical of any skin care brands now days, I hate that women everywhere are manipulated so much into being convinced they need the best. Exactly as people have mentioned on this thread, sun, moisture, genetics and general care are all thats needed.