The bathroom is the worst place to store your fragrances in. They´re best kept in a dark, cool place away from sunlight. They should last at least a few years, many do last much longer if stored correctly.
They certainly do! It's best to store them in a cool dark place and preferrably still in their boxes, heat and light are perfumes worst enemies! I have had ONE perfume of mine go bad on me, and that was because i left it out of its box sitting on my desk and it was in sunlight all day, it completely destroyed its smell and I had to chuck it.