Mentorship and knowledge sharing: growing by helping others grow

There is a common assumption among senior developers: mentorship is a sacrifice — you take time away from your own work to give it to someone else. Over the years, I have come to see that assumption as wrong. Mentorship is not a sacrifice; it is one of the most reliable tools for a senior developer’s own growth. This post explains why I think that.

Teaching tests your understanding

You think you truly understand something — until you have to explain it to someone else. The moment you start explaining, the gaps in your knowledge appear. If you cannot give a clear answer to “why do we do it this way?”, it means you memorized that thing; you didn’t actually understand it.

The questions people have asked me over the years became a map of my own blind spots. A junior’s “why is this necessary?” would often surface something I had been doing out of habit, the justification long forgotten. Mentorship shows you the real limits of your own knowledge while you are helping someone else grow.

Here’s a concrete example: a junior developer once asked me why I always use $request->validated() in Laravel. I said, “it guarantees the data has passed validation.” Then they followed up: “But what about when the controller is called independently of a form?” I had never asked myself that question before. A one-hour conversation led me to revisit my assumptions about form input security entirely.

Good mentorship is not giving answers

The biggest mistake I made in my early mentoring was thinking mentorship meant “telling the right answer.” Giving the answer is fast and feels good — but it teaches the other person to depend on you, not to think for themselves.

Good mentorship is modeling how to think. Instead of giving the answer, showing out loud how you arrived at it: “At this point I would wonder about X, I would look here, I would try this.” The goal is for the other person not to need you next time. A good mentor works to make themselves unnecessary.

Making that shift was harder than I expected. When you know the answer, staying quiet and letting the other person work through it — especially under time pressure — takes patience. But starting with “what would you do here, and why?” instead of “here’s how it’s done” is what allows that person to act independently the next time they face a similar problem.

Do not wait for a formal program

When people hear “mentorship” they think of formal matching programs. But most real mentorship happens inside daily work, in small moments:

• Opening space for the “why” when writing a pull request comment.
• Sharing your screen while solving a problem together, making your thought process visible.
• When documenting a decision, writing not just the outcome but the reasoning behind it.

None of these require a title or a program. All it takes is a decision to stop hoarding what you know.

Pull request comments are a particularly powerful tool in this regard. The difference between writing “this needs to be changed” and writing “here’s why this is a problem, what the alternative is, and what the trade-offs are” is significant. The first is a directive; the second is a teaching moment. The second takes longer, yes — but the person who reads that comment will remember that reasoning the next time they face a similar decision.

A side effect of sharing knowledge: clarity

To explain something to someone else, you first have to explain it to yourself. Writing does the same thing. One of the reasons I have kept this journal for years is precisely this: writing about a topic as if explaining it to someone else forces you to actually nail it down. Ideas can look clear in your head; the moment you start writing, the places where they fall short surface on their own.

Mentorship conversations create a similar clarifying effect. While guiding someone on a topic, you find yourself seeing that topic in higher resolution. Sometimes you even change your mind while you are explaining it.

Compounding returns

The career impact of sharing knowledge is slow but compounding. The people you help grow become, over time, the people you can trust and delegate to. Every concept you explain helps you hold that concept more clearly yourself. And after a while, you find yourself surrounded by a team that carries your way of thinking.

Seniority is not about hoarding what you know in order to make yourself indispensable. It is the opposite: transferring what you know so well that you leave behind people who can work independently of you. Growing others is not a byproduct of seniority — it is seniority itself.