The rules worth following, the traps worth avoiding, and when the 'best practice' is wrong for you.

Because code gets shared, copied, and stored in version control, so a password or API key written into it can leak to anyone with access, including the public if the code ever goes online. Leaked keys get abused within minutes by automated bots. Secrets belong in environment variables or a secrets manager, never in the code itself.

The essentials: serve everything over HTTPS, keep software and dependencies updated, use strong authentication and hashed passwords, validate all user input, protect against common attacks, keep secrets out of code, and take regular backups. Most breaches exploit basic gaps, not exotic techniques.

Technical debt is the future cost of shortcuts taken today. When you build something quick and messy to ship fast, you borrow time now and pay it back later as slower changes and more bugs. Like financial debt, a little can be smart, but too much left unpaid eventually cripples progress.

Usually, improve what you have (refactor) rather than starting over (rewrite). Rewrites are tempting but risky: they throw away years of fixes and edge cases, take longer than expected, and often recreate the same problems. Reserve a full rewrite for when the foundation genuinely can't support what you need.

Optimizing code before you know it's actually slow wastes effort and adds complexity for no real gain. You often optimize the wrong thing, since the real bottleneck is rarely where you'd guess. The rule of thumb: make it work, make it right, then make it fast, and only where measurement shows you need to.

Backups protect you from data loss, whether from a mistake, a failure, a hack, or ransomware. Without them, a single bad event can wipe out your site, database, and customer data permanently. How often depends on how much data you can afford to lose: daily is a common minimum, more for busy systems.

Because simple code is easier to understand, change, test, and fix, which is where most of a project's cost actually lives. Clever, complicated solutions feel impressive but slow everyone down later, including the person who wrote them. The best code is often the most boring and obvious.

Because code is read many more times than it's written, and usually by someone other than the author, including your future self. Clear names, sensible structure, and straightforward logic let people understand and safely change code. Clever tricks that save a few keystrokes cost hours of confusion later.

When your needs are standard and speed or budget matters more than being unique. A template or no-code tool is often the smart, honest choice for a straightforward business site, a landing page, or a first version to test an idea. Custom development is not automatically better.

Use an existing, well-supported tool for solved problems (authentication, payments, email, maps) and build custom only for what's genuinely unique to your business. Reinventing a common component wastes time and usually produces something worse than the battle-tested option, especially for security-critical parts.

Because fixing a flawed idea on paper costs minutes, while fixing it in built software costs days or weeks. A short planning step (clarifying what you're building, for whom, and why) prevents the far larger waste of building the wrong thing well. It's the cheapest quality step there is.

Mobile-first means designing for the smallest screen first, then expanding to larger ones, rather than designing for desktop and cramming it onto phones. You do it because most web traffic is mobile and Google indexes the mobile version of your site first, so the phone experience is the primary one, not an afterthought.

Because if a developer or agency holds your domain, hosting, code, or key accounts, you can be locked out of your own business, unable to make changes or move away without their cooperation. Owning these outright keeps you in control and free to switch providers whenever you choose.