Using the same namespaces aliases in all XAML files increases uniformity, readability, and discoverability of your XAML code. You should also consider always using the following standard namespace aliases for well-known namespaces:

  ✔  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

  ✔  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

  ✔  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

  ✔  xmlns:po="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options"

  ✔  xmlns:sys="clr-namespace:System;assembly=mscorlib"