I'd say set goals based of man hours and not physical dates. we want finish this game in 200,000 work hours with a staff 40 people. that's 5,000 hours of work per employee. if all employees work 40 hour weeks than, than that's 125 weeks of work. which is roughly 2.6 years so plan for. That would puts us roughly into a 2021 so plan for a 2022 release and be flexible with that date. Dont set the year in stone until the project is close to finish and dont target a specific quarter till the game is finished. If there is a significant time before release of the game use it to market the game. Keep an eye on what games are releasing and be ready to release the game early if the perfect release window presents itself before you're plan release date arrive. say like a big game or games get delayed leaving a month free of any major releases.