Which is better: long project planning down to the smallest detail or direct development without a plan and layouts?

Question

Project management

In order to start the project, I carefully even plan the project for a couple of months for a long time.
But sometimes when you need to show something to clients or at work, there is nothing to show because there is a plan, and development has just begun, and then at the core stage.

What to do if this is a project that can help a business, and there is only one developer (for example, me)?
How to be here? Whether it is worth thinking carefully about the project, the architecture of folders, files, design, and so on. Or all the same, immediately start programming?

Does anyone think that the way of planning with layouts is better and more productive than just jumping in and programming?

Update:
For those who think that I don't use MVC, Kanban, Agile, Time tracking, MindMap and so on. This is not it.
These things are used when there is already a layout or template, a draft of ideas with sketches, etc.

I mean before your project has moved from the idea stage to the development stage.

Answer 1

In my experience, these are two independent strategies. You can not drink hot tea and complain that it burns. As well as cold, and complain that it does not warm.
* If you are copying someone's project or business model. If you are doing something that others have been working for a long time. If you know exactly what brings in income, and what you need to save on. If there are already similar solutions on the market and they have long been known to users. Then only a serious approach to planning. The raw product will not take off.
* If you come up with something yourself. If there is nothing like it on the market. If only you know what your potential users need, start by deploying an empty draft project. You still no one knows your product, no one knows how to use it. The niche is free and while people hear that they need this service of yours, you will have time to grow up to the alpha version.
The problem with indie developers is that their plans may not match the requirements of users. What you do in an "analogue" project may simply not be needed by real people. You think that it is necessary, and they will prove to you that it is not. And throwing out what is in drafts or alpha is much easier than what you planned and licked for half a year or a year.

Answer 2

You are using a waterfall. By the way, I recommend it. Save money. Agile programming is good, but it increases the cost of development at times

Answer 3

Everything strongly depends on the horizon of your project, including the timing, budget and risks, the scope of the real world outside of programming, trust in the performers and influence on them (whose forces do you do - your organization or contractor).
The project must have specific goals, expressed in quantity and projected into money. If the project allows you to receive benefits starting from some stage, well, plan until the end of this stage.
PS

What to do if this is a project that can help a business, and there is only one developer (for example, me)?

This is not a project. It can be a hobby, an improvement program, training, but not a project.