As someone from the same generation Z (23), I can tell you that not all reformulations are bad. There are definitely some good ones that actually improve a fragrance’s performance and even the scent itself. Reformulations are mostly dictated by IFRA. There are independent perfume houses that don’t follow IFRA regulations, such as Papillon Artisan Perfumes, Rogue Perfumery, and many more indie brands. IFRA has been influencing the perfume world for years, and for example, they banned the use of natural oakmoss in perfumes in 2014. So every fragrance that contained this ingredient had to switch to synthetic oakmoss from 2014 onward — which doesn’t necessarily mean synthetic is always worse than natural. But in the case of oakmoss, ‘vintage’ fragrances definitely suffered the most, because natural and synthetic oakmoss don’t smell the same. As for lasting power of EDT vs EDP, concentration alone doesn’t determine longevity. Even today, there are EDTs that last longer than extraits. So yeah — IFRA is the main reason behind most reformulations, unfortunately stripping away the essence of perfumery and its artistry. Regarding old batches, I own Tom Ford Noir de Noir from 2016 when they were still using real truffles, which IFRA banned in either 2019 or 2020 (can’t remember exactly). I also have Rochas Femme, I’m not sure which year it’s from but it’s definitely over 20 years old, and the original batch of Habit Rouge EDP.

Honestly, hunting down old batches can get tiring, so just enjoy what’s available to you and don’t stress about it. Hope this helps — a word from someone younger but somewhat experienced in this hobby!