Formats and concentration
Body mist vs perfume
Body mist often describes a lighter fragrancing format, while perfume covers a range of concentrations and presentations. Naming is not uniform, so use the product's directions and exact description rather than expecting a fixed duration difference.
A HUME Fragrance buying guide

Compare intended use
Check where each product is designed to be applied. A body mist, hair mist and perfume may have different instructions even when their names sound related.
Read the composition cues
A mist version and perfume version of a familiar name may not have identical note balances. Judge the exact item rather than the name shared across a range.
Choose for actual habits
Portability, preferred presence and application style can matter as much as concentration. More frequent use of a larger mist is not automatically cheaper than another format.
Try this before you buy
Write which format best fits your intended occasion and compare complete prices rather than bottle volume alone.