Dear Ryu_chan
If I may weigh in. Jewelry is timeless but styles and aging are not. There are things I wore in my '20's and '30's that I wouldn't wear now-not because they don't fit, but because they're either no longer au courant, e.g., in fashion or they don't suit me anymore. For instance, my large Chanel camelia hoops went by the wayside last year-suddenly they looked too JLo-a look that may have been good once, but not anymore--at least for me. I sold them and someone else is now wearing them and loves them as much as I did.
My recommendation: buy what you love, buy what you will wear today, wear it to death, and if one day you decide they're no longer "you," you'll certainly be able to sell them and given the price increases, get your money out of them.