They keep track of the months, because what else are they going to do? Time has to have meaning on some smaller and more fathomable scale than seventy thousand lightyears, seventy-five years, one hundred and fifty-three individual lifespans, some shorter than others.
They keep track of the months, and Neelix marks their holidays and his, all of them, whether they want it or not. And if it doesn't make any sense to observe fundamentally seasonal holidays, replicate feasts to celebrate the harvest of fertile fields they may never see again, well, what else is ritual but a way to trick the mind into stillness?
And it does help. It's grounding. Until she hears herself say the words I thought we were still in April and the absurdity of it brings everything crashing down, the very idea of springtime suddenly an obscenity. She looks around and the ship that was their home is a leaden casket imperfectly sealed, an intrepid-class tomb torn half-open to the vacuum of space, and they are each of them ghosts who think they're better than death, and, disgusted, she thinks, April showers bring May—
Months, seasons, birthdays: unaffordable weaknesses.
The slate will be wiped clean and she will forget that she said it—she won't have said it—but something of it lingers behind her ribcage after that, some disquiet her body shouldn't remember. May comes around, and the twentieth is uneventful on the whole, and Chakotay gives her a pocket watch that is strange and beautiful and familiar all at once, and she has to smother a startling impulse to tell him to get it out of her sight, an impulse she chalks up to… what?
This is the third year that he has wished her a happy birthday (happy what?) but she does not feel like the person she was those other years. She feels like the silver of the watch, hardened, false, cold to the touch. She thanks Chakotay and—here is their ritual—he pretends not to want the things he can't have, and she pretends she doesn't know what she knows, and he smiles a little wistfully, and leaves. Like clockwork. Except that this year, she does not watch him go. This year, some nameless dread swells in her chest and crawls just beneath her skin until she feels like she might tear it off just to get to the bottom of what's happening to her, what happened to her.
Marking time by the Earth calendar never helps again. And she cannot endure the sight and sound of the pocket watch ticking, ticking, and like a woman condemned she marches herself to the mess hall to attend the festivities that Neelix organizes month, god, month after month, but she does not linger.
She can't bear it.
And she will never know why.