Although there is nothing like the experience of playing on a piano, electronic keyboards have many advantages over traditional pianos for the practicing musician. You can practice at a lower volume (or even use headphones!), you can interface with a computer to do amazing things using music technology, they are more portable, and they are less expensive.
However, there are a few pitfalls to avoid when picking out a new keyboard. All of them have to do with the student developing their musical muscles correctly and learning the correct technique. This is important because as they progress, properly developed muscles and correct technique will reduce the risk of injury, increase stamina, and improve the tone of their playing.
There are a few things to consider when purchasing a new keyboard. Of course, each new attribute will add to the cost, but each will also increase the useful life of your keyboard - as you won't be running out next year to buy a new keyboard that better suits your budding musician!
Full-Sized Keys:
Many keyboards use smaller keys than a piano so the actual keyboard can by physically smaller. Unfortunately, this causes a new student to create muscle memory on these smaller-than-normal keys, which can cause problems down the road when they go to perform at a recital or are asked to play at their talent show at school (both probably have traditional pianos!). It is wise to choose a keyboard with full-sized keys.
Weighted Keys:
Believe it or not, piano keys have weight. The physical act of pushing down a piano key causes a mechanical reaction within the piano to move a hammer, which in turn hits a string to make a sound. This physical action is lacking in electronic keyboards, but if a student wants to learn how to play piano, this physical weight is very important. Many keyboards mimic this physical action with what is called "weighted keys". This is important to pianists who are developing their hand muscles to properly play with correct technique. Each keyboard has its own "touch" and some come with little or no "weight". Make sure you play a few to discover the differences and choose the one that is right for you.
Velocity Sensitivity:
This is the technical term that means the harder you play the keyboard, the louder the note. As you can imagine, this is especially important to learn how to properly play dynamics! Without the ability to play loud and soft, it is tough to get the hang of being expressive.
No Less Than Four Octaves:
Learning on less than four octaves creates difficulties when learning how to play hands-together or learning to jump octaves. A beginner student will quickly outgrow a keyboard that has less than forty-two (42) keys (a common size, close to four octaves); A four octave keyboard may last a year or two, but eventually a student will need to use the entire keyboard. If you can, start with a full-sized keyboard right away, as we find it helps students better understand the "big picture" when it comes to learning concepts on the piano.