Developing programs without relying on third party libraries provides some unique advantages. As a programmer, I've found that taking on this challenge has really helped improve my skills.

When I don't use external code, I have full control over every line of the program. I don't have to worry about dependencies or changes breaking my work - I wrote all of the functionality myself so I understand it inside and out. This gives me freedom and flexibility to optimize and customize everything specifically for the task at hand.

Writing everything from scratch forces me to think through problems methodically rather than taking shortcuts. I have to research solutions and implement algorithms without falling back on library functions. This deeper problem-solving process has made me a stronger programmer.

I also gain a much stronger understanding of how my programs work at a low level. I can see exactly how all the pieces fit together since I built the whole puzzle myself. This level of insight isn't possible when relying on opaque third party code.

The programs I create this way tend to be leaner and more efficient as well. Without extra library code, my solutions are tailored precisely to the problem domain without unnecessary bloat. Performance and resource usage are top of mind in my design process.

Overall, taking on the challenge of developing without libraries, while more time-consuming, has really paid off in terms of the skills I've gained. I feel confident solving new problems from the ground up and producing high-quality, optimized code as a result. For projects where control or optimization are priorities, it's a very worthwhile approach.

It forces you to think through solutions from first principles rather than taking shortcuts with existing library functions. This leads to a deeper understanding of algorithms, data structures, and problem-solving approaches.

You have the flexibility to customize and optimize all aspects of your code specifically for your needs rather than being constrained by how a library implements something.

There is no risk of bugs, vulnerabilities, or unexpected behavior from library code that is outside your control or visibility. You have full insight into every line of code.

It encourages modular, reusable code design since you can't rely on libraries and need to break problems down into logical, independent modules/functions. This improves your overall coding skills.

The resulting programs are self-contained without dependencies, making them simpler to distribute, deploy, and maintain long-term without worrying about library compatibility or availability issues down the road.

It may lead to smaller, more lightweight programs without unnecessary code from libraries not optimized for your specific use case.

The downside is increased development time, as you have to research and implement everything from scratch. So it's best suited for projects where control, independence, security, or optimization are top priorities over initial speed of development. But it does strengthen programming abilities long-term.