How different is playing a soprano saxophone with playing an alto saxophone?

I really love soprano sax and planning to buy one soon. However, I can’t find a music school that teaches soprano sax. They teaches the alto one. If I can play an alto sax, does it mean I can easily play a soprano one too? How different is playing a soprano saxophone with playing an alto saxophone?

How many flutes does a Professional flute player usually have?

I have 2 flutes.
One Dean Yang (Open holed with a b foot and heavy)
and a Gemeinhardt (Closed hole for when i was a beginner)
I plan to continue playing my Dean Yang through out college.
but then, I noticed that a lot of people in my flute choir are getting a new flute.
How many flutes do flute players need?
Why do they keep changing their flutes?