Alex,

Another approach would be to bind the SpinIncrement property to the Value property and use a converter to set the increment.  For example:

XAML:

<Grid>
    <Grid.Resources>
        <local:SpinIncrementConverter x:Key="SpinIncrementConverter"/>
    </Grid.Resources>
    <igEditors:XamNumericEditor SpinButtonDisplayMode="Always" SpinIncrement="{Binding RelativeSource={RelativeSource Self}, Path=Value, Mode=OneWay, Converter={StaticResource SpinIncrementConverter}}"></igEditors:XamNumericEditor>
</Grid>

C#:

public class SpinIncrementConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        double newValue = 0;
        int increment = 1;
        if (value is double)
        {
            newValue = (double)value;


            if (newValue >= 100)
                increment = 10;
            if (newValue >= 1000)
                increment = 1000;
        }
        return increment;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Let me know if you have any questions with this matter.

Alex,

The SpinIncrement property of the XamNumericEditor controls how much the spin buttons change the value and you can handle the ValueChanged event and set it in the event handler:

private void NumericEditor_OnValueChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
    XamNumericEditor editor = sender as XamNumericEditor;
    double newValue = 0;
    if (e.NewValue is double)
        newValue = (double)e.NewValue;
    if (editor != null)
    {
        int increment = 1;
        if (newValue >= 100)
            increment = 10;
        if (newValue >= 1000)
            increment = 1000;
        editor.SpinIncrement = increment;
    }
}

Let me know if you have any questions.