Is it a good idea to practice on a digital piano?
Sgisela That sounds another positive point of having a digital piano. I rely on spatial memory and visual cues a lot playing the piano. So when I have to pay on someone else’s piano, I sometimes get totally lost, especially when I’m nervous 
. I’ll be using the digital piano for late night practice.
Rich-Galassini Thank you, Rich. Very interesting advice about how to practice on a digital. I’ll try it out when I have one!
Bellyman Totally agreed! I recently went to play at my university’s piano practice rooms a couple of times. The pianos are kind of worn. The keys are uneven and it’s very easy to play loud and very difficult to play softly. I had to compensate by playing very lightly/slowly. After that, I noticed that I started to make ghost notes on my own piano.
PianogrlNW Very cool! I never thought about using the digital for practicing duets. Being able to easily record a piece in the learning process is also a big plus. My teacher suggests that I do it regularly to hear what I did right or wrong, but I haven’t been able to. Thanks!
I have a Yamaha grand which I quite like. It is somewhat boisterous so the household noise it generates while practicing was an issue and I was semi-consciously curtailing my practice time and also always striving to play as softly as I possibly could (do NOT do this - bad habit!!!).
Since I got my digital Kawai MP11, both my practice time and consciousness issues went away 
. I do love having both and you could not take either one away from me. Easy to record yourself on the digital too for those self-criticizing moments. I always find it easy to go from one to the other even though they both have different keyboard feel, but close enough not to be a serious problem.
In terms of sound and expressivity, the grand wins every time of course but the digital is surprisingly rather convincing in its imitation. But it does remain just that - an imitation.
. That’s the primary reason for me to consider getting a digital so I can practice at night.
Rubens I think most people who try both instruments would say the P-525 has a lighter action than the ES920. But what matters most IMO is that you choose the one whose action most resembles that of your acoustic.
Thank you. That sounds like a great idea to help the transition between the digital and the acoustic. The action of our acoustic is on the heavier side, although it’s getting lighter (psychologically perhaps) as the new hammers break in. I may drive to the bigger city an hour away from us to try the digital pianos at a dealership.
One thing that a decent digital keyboard has going for it is that there is some adjustment of touch available. Can't do that with an acoustic, you've got what you've got unless you wanna spend some serious coin.
I say that with a bit of caution because generally, it's not the actual downweight or inertia of the key that's adjustable, but what happens from a feedback perspective can be altered significantly. There is a very wide range of sensitivity that is available on my Roland keyboard all the way from a very heavy feel and having to pound the keys very hard for minimal auditory reaction to a very light feel where even a light key touch will give a much more dynamic auditory reaction. (I've probably not said that quite right but hopefully you'll get the point.)
Also keep in mind that the action of a digital piano cannot be changed. But the sound engine can easily be replaced by hooking it up to a computer. Therefore when choosing a model, it would be wise to select the one with the better action over the one with better sound.
Playing on digital pianos of the Clavinova-type (by which I mean with that kind of action and sound, be it a slab or a cabinet) is absolutely fine. The touch weight is good enough for all practice. Let's not forget that 100 years ago pianists used to practice on silent keyboards which did not feel like pianos but had weights to mimic the touch. I honestly think that for the last 30 years - maybe even a bit longer - digital pianos have been absolutely fine for practice when it comes to learning notes especially, and refining some movements of technique. Now, you're not going to get much in the way of refined sound on an older digital, but you'll get enough to give you the vague idea. With newer digitals you can do much more refined practice. OK, it's not a grand piano and there are still big important differences but it's fine. Just be careful with how much force you are using and how much pedal you are using.
We actually have a Clavinova, though it's an old clunker and definitely more of an entry level model (CLP-811). My memories of an actual acoustic are rusty, but so far I haven't missed anything just yet. It feels real enough, though of course my skill level is still confined to "a little less loud here and more pedal there" 
The only issue I have is the very loud clack clacking of the keys, but that is probably because it's been gathering dust in the basement for more than two decades before I finally decided it was time to use it for more than just an ornament
I use my Yamaha P515 for repetitive type practicing, learning new notes, etc. as Joseph mentioned above. Then I refine on the acoustic. I still find the acoustic is way more responsive than digitals - and depending on many factors, including weather, temperature, etc., the tone does vary from day to day.
Bellyman One thing that a decent digital keyboard has going for it is that there is some adjustment of touch available. Can't do that with an acoustic, you've got what you've got unless you wanna spend some serious coin.
That is cool new information to me! I wonder if this function is only available in high end digitals. It sounds like a very useful feature for people (me) trying to adapt to playing on different pianos.