And if the responsible building authority is not on your side, there is no clear development plan, and you have to fight for your right to this house, the planning phase can stretch to 2 years. I speak from experience...
And we are not even the ones hit the hardest, I know a case where the dispute has been going on for 5 years about whether he can build the house as he wants or not. Well, many would have given in long ago (he wants a hip roof, but the municipality only wants to approve a gable roof - the whole thing is now being contested for the second time in administrative court. He will probably win, but the municipality has cost him 5 years with their nitpicking. You have to be able to endure that first), but here’s the question: is there a clear development plan? Is it one of those classic new development areas? On the one hand, it might be that you have to build very "standardized" there, on the other hand, you can maybe ask the future neighbors who already have an approved building plan and possibly also a general contractor/house builder. Often they find it quite appealing to have several construction sites close to each other and to be able to build according to a similar plan. That could, under certain circumstances and if you are very lucky, shorten the process a bit.