That's a good question. I have taken ballet and pointe. Pointe shoes need to be broken in. This way the shoe molds to your foot and forms an arch. I assume that it really depends on how beat up the shoes get before you need to replace them. If a new pair is used at each performance I would guess that the dancer has a collection of shoes previously broken in.
I know that Ice Skaters (who also have to have their skates seriously molded to their feet by breaking them in) have to replace them after every performance.
I thought I heard that it was the same for dancers who dance en pointe. :/ who knows!? lol
and all that I could do because of you was talk of love...
Professional ballet dancers often replace their shoes for each preformance, but unless you're a professional ballerina, that really isn't cost effective. It really depends on how much you dance and how much wear you put on the shoes.
Stephanie, actually skaters do not have to replace skates after every performance. When I skated, I got custom boots molded to my foot and they stayed with me until they broke down or I out-growed them. Skates take months to fully break in, and custom boots cost over $1000. So most skaters keep their boots for years.
As for pointe, I'd imagine they deal with it the same way. Keep them until they break down, and that depends on how much you use them.