Same as you - I stock up on the things that won't spoil, that I know I'll go through, and things that are expensive, so I can take advantage of discounts. I have personally had no success with anything drunk elephant I've tried from samples I've received- something they use just doesn't agree with my skin & is very stingy.
So at this year's sephora sale I got my year's supply of SKII essence, Anastasia Beverly Hills eyebrow pencils, Marc Jacobs eyeliners, hydrating hair masks & olaplex treatment/shampoo/conditioner. Normally I'd have more makeup to stock up on as well, but certainly not this year.
Melano CC has been on my list of things to try, and I have to admit oxidation is one of the reasons I haven't, I've been wondering if the shipping from asia matters with something as sensitive as C. But if you've NEVER seen oxidation, and still see results that's high praise - I've been cycling between skinceudicals and Timeless CE Ferulic and both turn orange on me before they're gone.