It's impossible to guess but we're aiming for 1 year. At that point I think we would cut up the game and call it complete. That would only be considered chapter or part 1 tho and that's so we can have a game to sell here on itch and on steam to keep us going. Then we would continue with part 2.
Both of us creators want to expand on this world and not abandon it. We've said that if we ever get tired of doing the main story after the first game is finnished we can always do a short VN on the side with the characters from this world. MC, Lisa, Emma and Emily where they for example could take a holiday and go on a cruise or they get stuck in a haunted house or anything we can think of, and that to us would feel brand new!