People base their understanding of the world on previous experiences. If there’s an established custom for your service that benefits a user, your service should conform to that custom. But be mindful that not all customs benefit users – some have been put in for the benefit of the organisation running the service, rather than users. Avoid customs that negatively affect your user or those that are inefficient or outdated
What this means in practice
Every element of the service works in a way that your users would recognise and understand from other, similar services they might use.
Your service does not expect your user to adjust their expectations or behaviour wildly from the rest of their experience of the world
You’ve achieved this when
Your user can use your service without having to learn new rules and ways of working that are different to the other services like yours that they might use.
How to do it
Research how your competitors work and look for patterns in what they do. Understand if there is an easier, more intuitive or more effective way of doing what you’re doing
If there is, test it to understand how different this is from your users’ existing expectations of how your service might work
Make sure that any changes you make are intuitive
Share the changes you make so that your patterns can become ubiquitous with other service providers and therefore more familiar with users.