The documentation that matters happens when you're in the thick of it, debugging at midnight and wondering why you started this project in the first place. That's when the customer feedback is still raw and you remember exactly why each approach failed.
Most builders wait until success to write anything down, and by then they've forgotten the real story. They create polished case studies with obvious lessons, but the actual learning happened months ago in the confusion.
By the time you're writing the success story, you've rationalized all the pivots and forgotten why you made half your decisions.
What to Document
The hardest part about documentation is knowing what's worth capturing. Everything feels important in the moment, but some things matter more than others.
After years of building and failing, I've found that certain types of documentation pay dividends while others just create noise.
1. Technical Decisions
Write down why you chose specific technical approaches while the constraints are fresh in your mind. Six months later when you're staring at weird architecture, you'll have the actual reasoning instead of trying to reverse-engineer your past self's logic.
Context changes everything. That hacky solution might have been the only option given your timeline and resources, but you won't remember that without documentation.
2. Failed Attempts
Screenshot every UI version, especially the ugly ones. Save features you built then deleted. Document approaches that seemed brilliant at 2am but failed completely. These failures reveal your blind spots and recurring assumptions.
The interfaces you're embarrassed by teach you what your biases are and who you're unconsciously designing for.
3. Customer Feedback
Save feedback verbatim, especially the harsh stuff that stings. The refund request explaining why your product is confusing. The detailed cancellation email. The potential customer explaining why they'll never buy. This feedback hurts but contains more truth than positive reviews.
4. Metrics and Pivot Moments
When things aren't working, document the numbers: user count when you pivoted, churn rate when you realized the problem, support tickets when the UX broke. Also capture why you pivoted, what options you considered, and your reasoning at that moment.
Without these numbers, you'll have vague memories like "it wasn't growing" instead of hard data that tells the real story.
Building Your System
A documentation system only works if you actually use it.
The perfect system you abandon after a week is worthless. The messy system you use daily becomes invaluable. Start simple and let it evolve based on what you actually need.
Start Simple
The best documentation tool is the one you'll actually use. For me, that's Apple Notes because it's everywhere with zero friction. Your tool might be voice memos, a physical notebook, or a Discord server with yourself. The tool matters less than the habit.
First stage is brain dumping everything with no structure. Random thoughts, debug notes, customer complaints, shower realizations about broken architecture. Let it be messy. You can organize later when you have energy.
Daily Practice
End of each work session, spend two minutes writing what happened. All you really need is something like "spent 3 hours on auth bug. Problem was timezone conversion." That's enough.
Weekly, review dumps and move important stuff to permanent storage. Monthly, write a one-paragraph summary to see the bigger arc beyond daily grinding.
Organized Storage
After a few weeks, patterns emerge. That's when I move from Notes to Notion, giving each project its own space:
- Screenshots: Every version, especially failures
- Customer feedback: Copied exactly, no editing
- Technical decisions: Why you chose X over Y
- Feature graveyard: What you built then removed
- Timeline: What happened versus what you planned
- Metrics: All numbers, especially embarrassing ones
This becomes searchable history for when you think "I've solved this before" on future projects.
Your Failures Folder
Creating a dedicated space for failures feels wrong at first. We're trained to hide failures, not preserve them. But those failures contain the most expensive lessons you'll ever learn, and forgetting them means you'll pay for the same education twice.
The Hard Part
Building a failures folder means repeatedly admitting defeat, which your ego hates. You'll tell yourself you learned the lesson without writing it down.
Three months later, you'll vaguely remember "it didn't work" but none of the specifics that would prevent repeating the mistake.
What Goes Inside
Each dead project gets its own folder with everything that tells the truth about what went wrong. Screenshots of what nobody wanted. Real usage metrics. Customer rejections. Your notes written while the failure was fresh, before you started making excuses.
Write while it still hurts.
Wait too long and your brain starts protecting you with comfortable lies about market timing and unfair competition.
The documentation should capture what you built, who you built it for, why you thought it would work, and exactly when you realized it wouldn't. These details fade fast but contain the actual lessons.
Using Documentation
Having documentation is only half the battle. The real value comes from actually using it to make better decisions. This means building habits around reviewing your documentation and finding ways to surface relevant lessons when you need them.
Pattern Recognition
With enough documentation, your patterns become obvious. Maybe you always add too many features. Maybe you consistently ignore certain types of feedback. Maybe you pivot too early or too late. These patterns only reveal themselves when documented across multiple projects.
I feed documentation to Claude when starting new projects. It catches patterns I'm blind to, similarities to past failures I don't want to see. External analysis finds things your brain naturally glosses over.
Pre-Flight Checklist
Before new projects, check your failures folder: Does this resemble anything that failed? Am I making similar assumptions? Are the early excitement signals the same as projects that went nowhere?
You're essentially using expensive data you already paid for with time and frustration.
Public vs Private
Keep the raw documentation private: screenshots that would kill credibility, feedback revealing how badly you misunderstood the market, metrics showing embarrassing usage numbers. This documentation works best when you can be completely honest without performing for an audience.
Share extracted lessons and patterns to help others without exposing your worst moments. People need to know you've failed, but they don't need the 3am keyboard crying sessions.
The Payoff
Documentation compounds like interest. Each project's documentation makes the next one smarter. After years, you're not guessing. You have data about what works for you specifically.
A ten-minute review of past documentation can save six months of building the wrong thing. You'll recognize patterns early: the type of excitement that doesn't convert to sales, the features that seem essential but kill simplicity, the market assumptions that never pan out.
Each save represents months not wasted. That's the ROI of documentation.
Start Tonight
Before closing your laptop tonight, write one thing about what you're building. Tomorrow, do it again. Don't worry about consistency or quality, just capture something true.
In a month you'll see patterns and in a year you'll have searchable history of everything you learned the hard way.
Start with one note daily about what happened. One screenshot weekly of what you built. One summary monthly of what you learned.
Build the habit first, improve the system later.
Your future self needs these breadcrumbs. The expensive mistake you're about to make might match something in your documentation, if you've been documenting.
Write it all down, especially when it hurts. The builders who win long-term learn from everything and check their notes before making the same mistake twice.
Start tonight. Your future projects are counting on it.