The development time is short so the update. But i would suggest the dev to take more time(4-5 months) and give big updates because with this speed I don't think we will ever be able to play the ending.
It really depends on the developer and whether or not he/she has any other people working on the project with them, TBH. I mean you could have one person dedicated to the coding/scripting part, another doing the writing and one person doing the rendering/animation. But that, obviously means the dev would have to make the money to be able to support such a team.
The dev I have been working with for the past several years is a one-man-band: meaning he does it all himself (which, in some aspects makes sense). If something gets screwed up, there's no one to blame for the error except the dev. Yet he's able to produce decent enough content on schedule every month. So each dev will obviously be different in their schedules depending on the situation (such as if creating VNs/games is their main source of income or if it's just a "side job") and how much content they want to put out in every update.
The hours it takes to do all of that alone is quite intensive, not to mention mind boggling. It also depends on how they create their games and what they use. Some are using AI rendering and voice acting (which is quite impressive, I'm not gonna lie. I've seen a few examples of it in action and my gawd... it's absolutely stunning). Others use bits of animation that aren't related to sex scenes at all, like motion (movement; i.e walking, moving their head, blinking their eyes, etc...) for example. Like, if you look at some games where the characters' faces appear beside the dialog box, their eyes are blinking and the head is moving from side-to-side or up and down. It blows me away the creativity used in VNs now-a- days. I don't think I would have the patience to do all of that, if I'm being honest.
