Ask most developers what slows them down and they'll point at the big, visible things: a slow CI pipeline, a flaky test suite, a monolith that takes four minutes to hot-reload. Fewer will mention the small utility they reach for a dozen times a day: the site that generates a UUID, the script that pretty-prints a JSON blob, the tab that encodes a Base64 string. Those tools are small enough to feel like they don't matter. In practice, they're used often enough that a bad one becomes a compounding tax on everything else you do.
A build system you touch once a sprint can afford to be clunky. A tool you open ten or twenty times a day can't, because every bit of friction gets multiplied by how often you hit it. If a UUID generator takes three extra clicks to get the format your database expects, or a JSON formatter chokes on trailing commas and gives you an unhelpful error instead of pointing at the exact character, that friction doesn't show up on a sprint retro. It just quietly erodes the hour you meant to spend on the actual feature.
The cost isn't only time lost to clicking around, either. Every time you stop mid-task to fight with a tool, you pay a context-switching cost getting back to what you were doing before. Research on task interruption consistently finds that resuming a complex task after a break takes measurably longer than the interruption itself. A workflow tool that interrupts you with confusing output, unnecessary steps, or a UI that changed since last time you used it isn't just annoying in the moment, it's taking a bite out of the deep-focus time you were trying to protect.
The more insidious cost is correctness. A password generator that isn't actually using a cryptographically secure random source will still hand you something that looks like a strong password, right up until someone attacks it. See Why Your Password Manager's Generator Might Be Weaker Than You Thinkfor how to actually check. A JSON formatter that silently reorders keys or drops a field you needed can send you chasing a bug that was never in your code at all. An encoding tool that gets confused with an encryption tool can leave you thinking you've protected a value that anyone can decode in one line, a mistake covered in more detail in Base64 Is Not Encryption. None of these failures announce themselves. They just sit in your codebase or your data until something downstream breaks, usually somewhere less convenient than where the tool was used.
Workflow utilities also tend to see things you wouldn't hand to just anyone: a real API key you're reformatting, a config file with a database URL in it, a plaintext string you're about to encrypt. If that tool runs on someone else's server, every paste is a small trust decision, whether or not you think about it that way. Most of these sites are free precisely because running them costs little, and free doesn't always mean the operator has a policy about what happens to what you paste in. A tool that runs entirely in your browser, with nothing sent anywhere, removes that decision from the equation instead of asking you to make it correctly every single time.
A handful of properties separate a tool worth keeping from one you'll eventually abandon for something better:
What to Look for in an Online Developer Utility Site goes through this checklist in more depth, tool by tool.
There's a version of this problem that's tempting to solve piecemeal: find the best UUID generator, then separately find the best JSON formatter, then the best password tool, bookmarking each one individually. That approach still leaves you with a handful of different trust models, different UI conventions, and different output formats to keep straight. The more effective fix is picking one place that handles the tools you reach for constantly, with a consistent interface and a single answer to the “where does my data go” question, rather than re-litigating that decision for every task. That's the actual argument for a toolkit over a scattered set of bookmarks, covered in more detail in The Developer's One-Stop Toolkit and the story behind why this site exists at all in Why I Built KeyForge.
None of this requires a big investment of time to fix. It requires noticing that the small tools in your workflow are worth the same scrutiny you'd give a dependency in your codebase, because functionally, that's what they are.