The pedal, bench, and music rest are the most important things to check. Does the pedal work OK? Close to what you are used to? Can you adjust the bench to what you want? Or do you need a cushion? Can you see the music (since you are using music)? How are the lights on the keys? Test how soft you can play. Playing loud is not usually a problem...
I would not play the whole piece. If you make a mistake at this point it will haunt your performance, and the time for practice is over...
Sam Great advice! Especially the pedal and pianissimo and practicing just before the performance.
I've had enough trouble with pedal action that I have a calendar reminder to check it every month for my piano club meeting. They meet at piano stores and the pianos can be on different height casters, have sticky pedals, etc.
I hadn't thought to try out pianissimo, but I can remember several times when I had trouble getting a quieter sound out of one their acoustics that I could easily get from my digital.
I also remember trying out my whole piece on the piano once before a meeting and made so many mistakes that I decided not to play at the meeting. Later in the meeting I felt better and played well, but I'd rather not have that happen again.
Thanks everyone, this is super helpful! Especially @Sam !
I would not play the whole piece. If you make a mistake at this point it will haunt your performance, and the time for practice is over...
Great way to put it!
@lilypad , ugh, I forgot about those grand piano dollies you sometimes see, where the piano is permanantly on the dolly so that it can easily be rolled around. I hate those because they make the pedal height so awkward. Hopefully it won't be on one of those, but I'll make it a point to check beforehand.
Re the bench, I always like a high bench, but there are never adustable benches in the lesson rooms we use, so I have a black towel folded up that I always use. Maybe I'll just take that....
Oh and I have my bluetooth foot pedal, which is always awkward because you have to bend down and put it underneath the piano. In regular times, that's awkward, but I recently hurt my back and I'm not super agile right now. 
A lot depends on how nervous you are on the day of the performance.
Stay focus, breathe normally. Stay calm and donāt rush.
Good luck.
@thepianoplayer416 thanks, I'll check out that video later.
But this question was more about acclimating to the recital piano.
I will be nervous, I assume. I gave up on trying to prevent that years ago. Now my approach is just to try to prevent the nerves from causing fullblown derailment.
ShiroKuro And if I do play it, should I do a ādress rehearsalā style play-through? Or a slow play-through?
On the day of a concert, I like to do a slowish, laid back play-through.
Sam Test how soft you can play
Very important. If you have a specific passage in the piece that should be really pianissimo, or one where a diminuendo goes to almost nothing, try that. If your piece has a big dynamic range, it's important to hear how the piano reacts at different levels. Just play simple chords and slowly go from ppp to fff.
I certainly wouldn't play the whole piece, but if you have another piece that you know really well, you could play through that to get comfortable with the instrument.
@ShiroKuro - you got a lot of good advice from @Sam . I would add that itās helpful to get an idea of what to expect from the sound, and how different this is from the piano(s) youāre used to playing. I understand that youāve got some other pieces that you almost decided to program, so Iād consider playing 5 or 10 bars of another piece thatās in a similar style to the one youāll be performing. Personally, I find that playing actual music gives me a better sense of what to expect from the instrument ā action, sound, and pedaling effectsā than just playing scales/arpeggios.
Sgisela I understand that youāve got some other pieces that you almost decided to program, so Iād consider playing 5 or 10 bars of another piece thatās in a similar style to the one youāll be performing. Personally, I find that playing actual music gives me a better sense of what to expect from the instrument ā action, sound, and pedaling effectsā than just playing scales/arpeggios.
Oh, good point!
Shoot. I donāt have anything else that has five sharps. That was why I thought a scale, because that way I could check all the keys Iāll play.
Anyway, Iāll figure something out.
It doesn't need to have five sharps. To get comfortable with the piano, play anything that you know well.
If you're really worried that the piano might have a defect, such as a unison out of tune or a damper that doesn't do it's job, you need to play a slowish chromatic scale through the whole range. If it turns out that there is a serious problem with the instrument just before the concert, you wont be the only one affected and emergency measures are called for: is there a piano tuner in the house, is there another piano...
But that shouldn't be the case. To get a feel for the piano, you don't need to play all the keys that are used in your piece. Just pick something you know and love, and play as much of it as you have time for.
MRC If you're really worried that the piano might have a defect
I probably shouldnāt worry about this! Itās just on my mind because last week, I went to play a public piano, thinking it would be good practice, but the C one octave below middle C was depressed, wouldnāt return and didnāt sound. As you can imagine, that had a significant impact on several of the pieces I was planning on playing!
I always tend to think of worse-cases and contingencies. But the recital is in a local church so Iām sure the piano is well-maintained.
@ShiroKuro how did it go?!?
Good luck! 
Test trills and other ornaments? I find those very a lot from piano to piano. Edit: oops, just saw the time. I'm probably too late ...
Enthusiastic but mediocre amateur.
(Iām in the U.S. eastern time zone)
