(Captain Obvious mantle on)
You are a software engineer and maybe you have a side project – something that you do at home in your spare time. If you don’t, go ahead and have one – no life outside is better than a few more hours of programming. Unwitty jokes aside, having a side project is indeed a very useful practice (read on).

A side-project is sometimes thought of as “the thing that would make you rich and you won’t have to program ever again”. It very rarely is, so we’d better view it as “the thing that would sound cool when I speak about it”. But apart from the motivational/coolness aspect, side-projects have a very important practical consequence – they make you a better programmer.

Of course, every extra hour of doing something makes you better at it, but a side-project is even better, because you are the one that makes all the decisions – what to do, how to do it, when to do it, what technologies to use. I’ll focus a bit more on the last point. Not only you can choose the technologies to use, but you can choose technologies that you don’t know yet (imagine going to your manager in the beginning of a project and and asking him to build it with a language or framework that nobody on the team has ever used).

And that’s what I’m doing – for most of my side-project I choose technologies that I haven’t used before. I get to learn new frameworks, tools and languages (a.k.a. “technology”), and get relatively good with them. That’s the way I learned JSF, Android, Scala, AWS and more. Learning a technology by itself is not the most motivating endeavor, but learning it as part of a project; as part of building something meaningful, is a different thing – it comes naturally.

The obvious practical bonus of all this is that you become more “hireable”. Having a technology in your skillset makes you more eligible for certain positions than other people – knowing a bit of scala and AWS makes you way more qualified for a “scala full-stack engineer” than someone with just Java and Linux knowledge. Another scenario is when a new project starts and you get to pick the technologies, you can now say “I have experience with JSF, let’s build the front-end with that” (and that’s exactly what has happened to me).

Now, a clarification is due about the “new” word in the title. I don’t intend it to mean “untested, overhyped crap”, I mostly mean “new to you”, something that you haven’t used. It might be an already stable technology, or something that is gaining traction but your conservative company is never going to try. Of course, trying something “fresh” is also good, as being an early-adopter is sometimes rewarding.

Should you make side-projects with technologies you are familiar with? Of course, and I’ve done so as well. If the subject of the project is way more interesting than the technologies themselves (e.g. an algorithmic composer). But it is way better to use at least one new thing.

By the way, that’s not relevant only for “youngsters”. The “big, fat architect” also needs a bit of the side project experience too, otherwise he risks being irrelevant pretty soon.

In a way I think side projects are the way for developers to enrich their skillset and to be up to date. Learning only the technologies you need at work can make you forget how to learn; forget what programmers’ curiosity is – and that’s just bad. And constantly exploring the programming world not only gives you particular skills with a given technology, but also broadens your general engineering mindset.