Design consistency issues when allowing the user to change design

1. How will an inconsistent user interface affect the user?
2. What is design inconsistency?
3. What is design consistency?

How will an inconsistent user interface affect the user?

User interfaces that aren't consistent often yield confused and frustrated users and can drive even the most promising products to failure.

What is design inconsistency?

Every other element within your design creates a pattern (consistency) so that, when the pattern is broken (inconsistency), it stands out. If you implement too much inconsistency, all patterns dissolve into chaos. Overall, the more inconsistency you apply, the less each individual occurrence draws attention.

What is design consistency?

Consistency in design is about making elements uniform — having them look and behave the same way. We often hear designers talk about consistent navigation, consistent page layouts, or consistent control elements. In each case, the designer is looking for a way to leverage the usability by creating uniformity.