I use to just try to figure out what happened with other players in advance for some occasions.
Last time we just wrote some ic'ish posts in our forums which resulted in our chars having built their new house. After all it took maybe 15mins for me rl-time and described several hours "ingame"-time (lol)
But I also just claim anything that comes to my mind and fits the latest events in my char's life, be it sleeping, hunting, leathercrafting.. whatever is needed.
but I'm pretty sure Yliakum people sleep as long as 'normal' people do
I am more wondering about Yliakum people being awake nonstop much longer than "normal" people. And by that, day-night-change loses any significance.
Or did anyone of you ever check the ingame-time, say after 30mins of playing, its 1am ingame and you get your char "home" to rp sleeping for the next few hours rl-time?

After all, days and nights dont matter, use it when you just can make use of it, and ignore it when night doesnt fit your plans, I am sure anyway that the vast majority doesnt care about ingame-time, except for occasions like ways to greet ("good morning" etc.)