It's the ultimate luxury for women everywhere – but so easy to get wrong…
Do your research first. Look at the bottles in the recipient's bedroom or bathroom – and disregard any with dust gathering around the neck. Concentrate on those that have been obviously frequently used.
If someone likes a fragrance from one house, they may like others from the same brand. Even better, try to find out which family the fragrance belongs to. Women's scents are divided into floral, chypre and oriental; men's into fougere, chypre and oriental. Someone who likes light girly florals may not be impressed with a spicy oriental, so try to stick to the same 'family'.
If you don't want to risk getting it wrong, maybe buy a selection of small sample bottles – you can find them at the counter at places such as Superdrug – and wrap them up with a hand-written note promising to buy the full size of the most popular.