A sample usually lasts me a long time too.. and I don't skimp on application. For pheros, I apply to my torso, cleavage, inside of elbows, back of neck (I have short hair). For perfume only, all those places plus my wrists, my collarbone and under my ears.
Of course, a sample may last so long for me because I have so much perfume, I don't wear the same thing all the time! Variety is the spice of life!