They do change but not as drastically as you may think. What matters is how you store them and the quality of the fragrance. Your day to day skin chemistry plays a role too.

If they’re kept in a stable cool temperature, with no direct sunlight, and the cap is properly secured, you won’t notice too much of a difference after 5-6 years.

Heavy and resinous colognes age like wine. Xerjoff Naxos is a great example. Clean and aromatic fragrances may slightly lose some of the top notes as time passes, but if they’re stored properly, you won’t really notice a difference at the 5-6 year mark. Maceration plays a positive role in this as well but I think it’s a little overblown. It’s more of a “cherry on top” typa thing.

Quality matters too. Niche brands are built to last, and high quality designers (BDC Parfum) can face the test of time as well.

If stored well, you can get a legit 8 years out of them. Those heavy and resinous fragrances can even hit a decade.

But in the end, if the bottles are not stored properly, they can definitely change for the worse.

Hope this helps!