Lost Ark

Lost Ark is a raid MMO where the entire structure of play is built around a weekly reset. Guilds run a fixed weekly raid cycle, and the value of doing those raids decays as the week goes on, so a "next update" that lands mid-week resets everyone's progress economy at once. That is why the weekly reset matters more than most patches.

On top of that, Lost Ark gets scheduled content updates on a cadence roughly monthly, and each one brings a new dungeon, guardian raid, or region. Those are the headline events. Between them, balance patches arrive faster and change class tuning, drop rates, and currency sources.

The part worth understanding before you plan around a date: the region structure means new content is gated. A new region's raids usually require you to have completed the previous region's progression first, so the release date of a dungeon is not the date you can meaningfully attempt it. There is usually a buffer of days to weeks between the two.

There is also a version of this game's schedule that depends on regional servers, and those do not always move together. If you play on a non-English client you may see content arrive on a different day than the global schedule suggests, which is worth confirming rather than assuming before you take an evening off work.