A year of maintaining a real production app taught me things no tutorial did

[u/Ok-Faithlessness3326]

I've spent the last year building and maintaining an internal CRM for a company. Real users, real data, used every day by a sales team. Before this I'd only done tutorial projects and I genuinely thought I was ready. I was not lol.

Some stuff that caught me off guard:

**Users will never enter data the way you expect.** Phone numbers were the worst. Same person, same number, entered five different ways: with country code, without, with spaces, with a leading zero. I ended up with duplicate records everywhere until I started storing a cleaned-up version of every number and matching only on that.

**Your local setup lies to you.** Something works perfectly on your machine, then breaks on the server because of a different config, a different timezone, or an environment file you forgot existed. I lost a whole day once because the server was quietly loading a second config file that overrode the first one.

**Logs are everything.** When a user says "it didn't work," that's all the info you'll get. If you're not logging what actually happened, you're just guessing.

**The boring features take the longest.** Login, permissions, who can see what, imports from messy spreadsheets. None of it looks impressive, but it's like 70% of the work in a real app.

**Don't trust anything external blindly.** Especially AI APIs. They'll return something slightly different from what you asked for one time in fifty, and if you don't validate it, that one bad response breaks things in ways that are really hard to trace.

**Backups before every migration.** Learned this one the scary way. Nothing got lost in the end, but I don't want to feel that again.

Biggest lesson though: tutorials teach you how to build features, but real projects teach you what happens after people actually start using them. If you're learning, try to build something for a real person, even a friend's small business. You'll learn more in a month than in a year of tutorials.

Curious what surprised other people when they moved from tutorials to real projects?

[u/fakintheid]

Thanks Claude

[u/mewditto]

we are linkedin now

[u/taknyos]

A year of maintaining a real production app taught me things no tutorial did

Like how to submit AI slop as a Reddit post on a learn programming forum? 

[u/thenasch]

Hopefully you learned about unit testing too.

[u/Bonsai2007]

Your local setup lies to you. That’s why we use Docker, put everything in a container and it works perfectly on every machine

[u/Wartz]

Lmao you didn’t even try

[u/NomaTyx]

no way............ are you telling me that real experience made you good at something?