I tell you one thing: I'm 50 (fif-ty!) and I still spend money on things I don't really need.
The only thing that comes with age, you stop regretting it. At my age, I can always blame it at my "younger self", at your age, well, blame it on the genes or evolution or something ...
I've always had the stance on money (and I never had much) is, easy come, easy go. And, to use a modern metaphor, you need a certain buffer to rely on in emergencies. How big that is depends on your lifestyle; for me, a thousand euros are enough, and as you know from Windows buffering files, the amount can vary. LARGELY!
But the least thing I'd do is invest in expensive christmas gifts. Besides that I'm an atheist, they'll never give you a decent return.
Can there be a reason why flight tickets around christmas get so expensive? Do you really think it's that people are flying HOME to their families, or isn't it rather the other direction?