I've never completely finished a bottle of perfume as of yet, but I have maybe one or two uses left of my Nina, by Nina Ricci left. Its taken me maybe 4 months. I LOVE it so much. I got a new bottle for xmas, which is 80ml I think, and the old bottle was only 30ml, but I like having the small bottle to carry about with me, the big one weighs so much. so I'm not using the little one yet.
And I have a bottle of Hanae Mori Butterfly that I've almost used up, but I lost it and its almost two years old now so it probably doesn't smell very good anymore.