Generally we have a meeting before where we sort through suggestions, then we pick what we want to do/create.
Clearly with more caveats, hours of discussion and thinking about how implementation would go. Anything model related was squashed when Hancock left, so now we're playing catchup between Midnight and Guac.
Essentially we do 4 Major updates a year, and 4 mini "bridge" updates. We tend to save big things for the content updates and smaller things for said bridge updates. Generally before a big update we look at the server as a whole and figure out what needs a refresh. On mini updates, we do the same thing on a smaller scale (hence the HVO focus and skill adjustments here). There is no real rhyme or reason, we just do what we think is beneficial in that moment, and unfortunately that means some suggestions may sit longer, whether it's due to inability to create/make them at this time or just not something we think fits in the current push.