In a rush to move quickly, startups often get sloppy with one of the most important habits for continuous learning and improvement: writing stuff down.

If you don't write stuff down, it's impossible for your whole organization to continuously learn and improve.

Every time you do something that another team member has to do later, you should take an extra 5-10 minutes to write it down or even sketch it out. If you make documentation digital and shareable for everyone on the team, everything will improve more quickly from building product to onboarding new team members.

Ben Horowitz of Andreessen Horowitz says:

Good product managers gather information from engineering informally and verbally, but good product managers give direction in writing to engineering….Written communication to engineering is superior because it is more consistent across an entire product team, it is more lasting, it raises accountability.

If team members want to know why a certain process is in place, they can look at all the documentation behind it and understand the decision behind it. The only way to rapidly improve as a small product team is to have everyone involved in improvement, and the only way to achieve this is by putting pen to paper.

Why writing stuff down matters:

• As a company, it's how you build your knowledge base, and create a living repository of everything you've learned developing product. That's the foundation you build on for learning with each iteration and product experiment.
• It forces your processes, people, and quality of thought to be better. As Intel CEO Andy Grove once said, documentation is often "more a medium of self-discipline than a way to communicate information."