Recording has been discussed above, in the "Computer Software" section. However, because nearly all digital pianos come with at least basic recording capability, it deserves a bit more attention. You may say that you have no intention of recording your music for others to hear, but in ignoring the instrument's ability to record what you've played, you may be overlooking one of the simplest ways of improving your playing. Whether you're just starting to play or are beginning to learn a new piece, being able to hear what you've just played is a learning accelerator.
I know what you're thinking: "I heard it while I was playing it." While most professional musicians have reached a level where they can effectively split their attention between the physical act of playing the instrument and the mental act of critically listening to what they're playing, few of the rest of us can do this. Recording and listening to yourself will reveal elements of your playing that you never noticed while you were playing, and will allow you to see where to make changes in your performance. This is even more useful when working with a teacher. Imagine listening with your teacher, music score in hand, and pausing the playback to discuss what you did in a particular measure. This is one of many reasons piano teachers are adding digital pianos to their studios; they're great learning tools.
All of the amazing capabilities of the modern digital piano are of little value if the player can't figure out how to use them, or can't access them quickly while playing. The considerations here are the location, spacing, grouping, size, shape, colors, and labeling of the controls. In the case of instruments with displays, considerations include the size, resolution, and color capabilities of the screen and—more important—the logic behind its operation.
Also worth considering is the placement of connections you'll use often. If you frequently switch back and forth between speakers and headphones, you'll want to make sure the headphone jack is easy to locate by sight or feel, and that the cord will be out of your way when plugged in. If you'll be using a USB memory device to transfer files between instruments or between the instrument and a computer, make sure the USB port is easy to get to. In newer designs, a USB port is placed above the keyboard level for easy access, as opposed to earlier models in which the port was below the keyboard or on the instrument's rear panel.
We can't leave the subject of user interfaces without discussing the owner's manual. A well-written manual can make it a pleasure to learn a new instrument, and a bad manual can be worse than useless. This is particularly important for higher-end instruments. Fortunately, many manufacturers allow you to download the manuals for their instruments. This lets you compare this critical aspect of the instruments you're considering. The manual should be thoroughly indexed, and clearly written and illustrated. Third-party tutorials are available for some instruments, especially the more complex models. These tutorials step you through the model's functions with audio or video instructions, and provide an alternative to sitting down with the manual.
Because digital technology advances at a blistering pace relative to acoustic piano technology, there is much less interest in used digitals than in used acoustics. Many of today's digital pianos eclipse the capabilities of the models of even five years ago. Combine this technological advancement with the fact that support of older instruments may be limited—after production of a particular model ceases, electronics manufacturers are required to maintain replacement parts for only seven years—and investing in older models becomes worthy of serious second thoughts.
Owner's manuals no longer accompany many used instruments. If you find an interesting used instrument, make sure that the manual is either still with it, or is readily available from the manufacturer or on the Internet. The manual is your best tool for ensuring that everything on the instrument still works correctly. It's not simply a matter of pressing every key, button, and pedal to see that they work; to thoroughly check the instrument, you also need to know what some of the less obvious controls are supposed to do. None of this is to say that used instruments should be avoided—I've played ten-year-old digital pianos that worked perfectly. But when considering an older digital piano, extra care should be exercised.
You've decided what type of instrument you're looking for and how much you're going to spend (unless, of course you hear something that just knocks your socks off, and your budget along with them). There are still a couple of last steps in preparation for the hunt.
If you don't already have a good set of headphones, this is the time to get them. Headphones are probably the most widely used accessory for digital pianos, and it's a sure bet that you, or another player in the house, will need them or wish the other player were using them—and they're an invaluable tool for auditioning digital pianos. I've always found it odd that people will agonize over the choice of a digital piano, spend hundreds—frequently thousands—of dollars on their choice, and then listen to it through $19.95 headphones. (See "Digital Piano Basics, Part 2" [in Acoustic & Digital Piano Buyer] for a more detailed discussion of headphones.)
The final step is to "calibrate" your ears. Listen to recordings of solo piano. Listen to what you enjoy, be it jazz, classical, or ragtime—just listen a lot. For part of this listening, use the headphones you bought for your digital piano. This will embed in your head, as a benchmark, the sound of high-quality acoustic pianos. One of the great things about digital pianos is that if you love, say, honky-tonk piano, all you have to do is make sure the instruments you're considering have a Honky-Tonk setting. Then you can "change pianos" at will. But for the moment, listen to the best piano recordings you can get your ears on.
Introduction to Buying
a Digital Piano