I think longevity and sillage become factors when deciding which perfume to put on. I have several strong perfumes (Black Opium, a Tauer, some of the 4160s and samples from Xerjoff, Kurkdjian and so on). They last probably 4-5 hrs and then a few hours more as a strong skin scent. But I wouldn’t like to spray them and go straight out into company.
Then there are a lot of the high street perfumes which are designed to have delightful top notes that last for an hour or two but dry down to a barely-there boring skin scent. For me, that would include the likes of Chanel Gabrielle, Gucci Guilty, Prada Candy Gloss (I love the plastic note in this!). I’m happy to use testers but wouldn’t actually buy a full bottle because only the beginning bit of the perfume is interesting.
There are a number of cheap and cheerful perfumes which I enjoy. Some of them have surprising longevity (SJP Covet, Madonna’s Truth or Dare (and TorD Naked), Pharrell Williams Girl) but a lot of them don’t (the Britney Spears, Body Shop Italian Summer Fig). But they’re so cheap you can respray with abandon 😀
I think my favourite perfumes are the “quiet beauties”. They are not too strong to start with, have lowish sillage, last maybe 3-4 hours but then have a “wafting about” stage of up to another 3-4 hrs. I include in this category several of the 4160s, Balmain Ivoire, Stendhal Elixir Blanc, Prada Infusion D’Iris and of course, my beautiful Elephant (although the top notes in this are quite strong to begin with!).