(That has a purely pragmatic excuse as well, of course. It's vastly cheaper to send out the same people who are already in space for successive missions, rather than train a green dirtsider and haul them up out of a terrestrial gravity well. Radiation shielding, vitamin D and calcium supplements, and high-bandwidth communications are a cheap price to pay in comparison to a FNG every mission.)
Time grinds out here. Sitri can barely stand it. The communications lag grew worse and worse on the way out, to the point that the lag became more annoying to Sitri's permanently-connected sensibilities than complete shutdown, so she killed all but the essential data feeds back to the L4 base. Now she flips them back on once every thirty hours or so for a burst from her readers and some old social networks that she still visits only on habit. Most of the time, she's gone through everything an hour after arrival and sent any outgoing responses, to wait another day for any links she's opened, videos requested, or webcomic archives to pore through. Condensing everything down like that in one burst has made her realize exactly how much time she wasted every day browsing through metaspace, looking for updates and poking around for anything of interest. Sitri could be a lot more productive like this, if there was anything to do most days. The irony doesn't escape her.
Reckoning gets real funny real fast. Years have no strict meaning when you're not in a regular orbit or subject to seasons, and months break down too. Days go out the window even faster, as people adjust to live independent of the sun's rise and fall (a trend begun more than a century before with the incandescent light bulb anyway, now cemented out in space). Hours hold on through habit, and with the artificially imposed schedule of check-ins at least once every sixty. Most people check in a lot more regularly than that, though Sitri has been slipping farther to the outer edge as time has gone by.
A lot of other people out here in the void have started reckoning by the second, as if that little slice of time is any less arbitrary than any other. Sitri tried it for a while, but gave up after the first million seconds. The numbers ticked up encouragingly at the rate of one second per second, but that did nothing to keep the minutes and hours from bearing down inexorably upon her stimulus-deprived psyche.