I've never seen Kos Mos, Aegis, Yuki Nagato, or any other unique construct get even just a little bit tired, for any reason, even when they perpetually work double-shifts that would exhaust any other girl in just two turns.
I have, however, seen the Windows girls (random contructs) get tired, sometimes all-too-easily. And then it's as if they need two months vacation just to get to working order.
Actually, that may be a bug.