Everything longer than a month is a huge red flag to me, especially if it's not finished or still in alpha/pre alpha raw version. it means the dev is another cuck$ucker that's just milking its audience
Anything over 4 months for me then I loose interest in the title and or forgot the game exists and usually after that much time there bullshit small updates I've noticed
I need at least 2 updates a year for a game that I really like, and for any other games if I don't get an update every other 3 to 4 months I lose interest.
I would say 2-3 Months but if its a good dev that has proven they can deliver good and a sizable amount of content then I would say 4-5 Months would be fine but It would have to be worth the wait if not then that dev would lose my confidence.
For me It depends on how much content a developer puts out and the overall quality of what is released. A good example of this would be v0.8 of Perfect Pitch which took a year too come out but was a such a good update that i found myself stunned at the effort the Dev put in.
So that being said if the content is great and of high quality I'd be willing to wait a year at maximum for a Dev. Otherwise It goes into the 6 month range for regular devs.
I believe it depends a lot on the game, but for me after a maximum of 1 month, after that it starts to get annoying waiting because when a new version comes out, it usually comes out with 20 to 30 minutes of content at most and this is extremely frustrating. Of course it depends from project to project, but I've come across months of waiting for the release of an extremely dirty and small update.
There is no too long because I don't wait for updates. I play through the available content, put the game in my backlog and pull it from there again months or years later depending on interest.
If it takes so long that I forget who the characters are or what happened in the story then I'm unlikely to pick it up again. How long does it take for me to forget those things depends on how interesting the game was in the first place so it depends from game to game.
I feel as though I've always been way too forgiving in this matter. Granted if its a single dev, thats usually what gets me in this. However if a deadline is set, then yes I'd have to agree with what a lot of others have said, 3 months over deadline is really pushing it
2-3 months, but if the updates are chunkier i could wait longer without dropping it, thou everything longer than 6 months with no notice or news kill my interest