i'd love to hear what details you keep track of and how!
for me, some of the most useful data are:
- source (e.g., online platform or person's name)
- estimated fill level at time of acquisition (i often get partial bottles)
- cost/mL
- bottle's full volume
- size (sample, mini, travel, full)
- dispenser (atomizer, splash, dabber vial, applicator wand)
- date decanted
- date gifted or returned to someone
- date emptied
as an example: per source, i could break down costs/mL, my personal ratings, and release years.
local ad-posting sites and estate sales have been excellent cost-wise while most online shopping platforms are pricier. i've also used cost/mL (looking at my overall collection as well as excluding costly outliers and/or free gifts) to determine if something i want to get is reasonably priced in the context of my overall spending habits.
there is a significant relationship between my personal rating and the purchase source. perfumes i buy myself on secondary market platforms are generally higher rated than ones i received as gifts, which makes sense since i sought out the purchase.
on average, certain sources (i.e. people) have gifted me much older perfumes with respect to release dates than those I buy, as the gifts are usually hand-me-downs from people's much younger years.
i also have a column for Luca Turin's and/or Tania Sanchez's rating of the perfume if applicable, and i can see many perfumes i've bought for myself have been highly ranked by them. this is because when i first started looking into fragrance, i browsed some of their books and chose to sample perfumes if the LT/TS reviews were interesting.
my data collection has been useful for generating (via pivot table) various lists of fragrances meeting certain criteria, if i'm looking for something in particular.
lately, i've been filtering for splash bottles of fragrances i've never decanted, from which i'll select what to fill my emptied sample vials with atomizers with - in an attempt to approximate the scent of a full size bottle with atomizer and to test for differences between dabbed and sprayed.
i'll pull a unique list of perfumes (no extra weight given to duplicates), filtering out emptied or removed scents, which i then pass to a randomizer formula to pick a perfume to wear.
generally speaking, i can grab a list based on any of the aforementioned characteristics to make a new "pool" from which i want to select my scent(s) of the day, like if i want focus on a certain segment of my collection (e.g., low-fill mini splash bottles that i got for free).