My first game that I finished was made over the course of about 5 years, but I took many long breaks in between. Counting only activity, it was probably around 6 months of working on it.
Second game, only playable demo, was done in like 2 years, but again with like 6 months of actively working on it.
Third game, finished, took about 2 months to finish it, then another several months of finetuning and updating it to work out bugs and adding extra stuff to it. The last update was done exactly 1 year after the initial release, and not interested in doing more with it.
Current project, started since MZ release and still working on the combat system, setting up skills and passives. Got nothing really else besides it. Combat always takes the most time for me, but it's the thing I find most important as well as most fun to work on.