Another topic that involves a lot of thinking is... choosing an instrument. Guitar, flute, piano, violin... are among the most popular ones. Picking one or another will depend on personal preferences, budget, space at home (a piano needs a bigger corner than a flute), etc.
My experience tells me that piano is "easy" to start with (you "just" have to press the keys and the sound will be there) and the violín is much harder to start with (this is specially true when you compare it with the piano): before making any music you have to learn to hold the violín itself AND the bow (this step barely counts when speaking about the piano, since it "stands" there and the pianist just sits in front of it). And after you've learnt how to hold both (instrument+bow) let's start to make music... First sounds in violin pupils aren't as pleasant as one might listen from concerts or recordings!
A bright side of choosing violin over the piano is that you could always bring your instrument wherever you go while the piano... well, let's say it's not light enough to move it often :) And, if the student is a young child, the instrument will "grow" with him.
Another aspect to consider is that buying a piano means a big investment (you can always rent it, but in the long run, you will end up buying one... maybe second hand, but buying) while violins (and guitar or flute) are cheaper (also here, you have the possibility to choose from brand new instruments or second hand instruments).
There are more things involved in the task of selecting what instrument suits you, or your kid. If you want to know more about it, feel free to ask!
Comments