It's a long time... longer than he can remember being alive, but shorter than the span of his collective existence, which is still only a fraction of the time people in the Carnival have been alive for. But that's only because YoRHa are the latest android models. Other models... They've lived for much, much longer.

"It's longer than any other time I've been apart from her."

But it doesn't matter how long he has to be away from her, as long as they will meet again.

"I'll be fine. I used to work solo missions before I met her, so I can handle myself." And he's not really alone here... "How long have you been alive for anyway? You sounded unsure."