Why stairs wait until after the first night
Everything about a first night is already at maximum novelty: new smells, new voices, the loss of her littermates, and a car journey behind her. Stairs add a physical puzzle — open risers she could slip through, banister gaps at kitten height, a long fall she cannot judge — at exactly the moment she is most tired and least coordinated. A frightened kitten bolting on unfamiliar stairs can fall or wedge herself somewhere unreachable, and a kitten who learns the house during a stressful night files the whole place as alarming. One calm room teaches her she is safe here; the staircase will still be there in daylight, when she can learn it with a rested brain.
Build the single-floor first-night room
Choose a small, quiet room on one level — ideally where she will ultimately sleep — and set it up before she arrives: tray in one corner, food and water well away from it, a low bed with a soft blanket, a scratching post, and a hiding box she can retreat into and be left alone inside. Block the gap under the door if she is tiny enough to squeeze through, remove cables and small objects, and close windows. If the only available room opens onto a landing, fit a closed door or a secure barrier as your boundary. Stay with her in the room through the evening, let her explore it in her own time, and keep visitors and resident pets for tomorrow.
Teach the stairs in daylight, in stages
Once she is eating, playing, and using her tray confidently — usually after a few days — open the stair lesson in the morning, not at bedtime. Start at the bottom with a treat on the first step or two and let her climb as far as she chooses, staying beside her on the stairs so your body blocks a tumble without grabbing at her. Practise going down as deliberately as going up, since descent, with her weight pitching forward, is the skill kittens misjudge. Check your staircase through kitten eyes first: baluster spacing she could push her head through, loose stair runners, and landing clutter all need fixing before she has free access, and open-tread stairs may need to stay gated for longer.
Decide the household stair rules together
Until she is a confident stair user, the rule is simple and shared: stairs are gated or doors stay closed, she is never carried up and down as a game that encourages leaping from arms, and children do not chase her near the staircase. At night she continues sleeping in her safe room even once days expand, until stair confidence and tray reliability are both solid on every floor she can reach — and if she will range across floors, she needs a tray on the levels she uses most. A fall, a limp, or reluctance to bear weight after any stair mishap always warrants a prompt call to your veterinarian. Writing the first-night setup and the current stair rule into KinsLe Family Sharing means a partner or older child coming home late follows the same closed-door plan instead of improvising a grand tour.