A tool answers "how do I do this?" — a guide answers "why does it work that way, and what should I actually choose?" These guides exist because the second question is the one that saves you from rejected passport photos, loans that cost double what they looked like, and passwords that fall in two seconds.
Every guide here follows the same rules we apply to the tools themselves: written in-house, tested with real numbers (when we compare debt strategies, we run the simulation and publish the exact results), kept honest about trade-offs, and updated when facts change. Where a guide pairs with a tool, the worked example uses that tool — so you can reproduce every number yourself in a couple of minutes.
New guides ship regularly alongside new tools. If there's a topic you want explained properly, send it in — several of these started as reader requests.