I prefer to have X1.5-2 spacing between luines in writing emails' using outlook 2010. I can do it every time seperately' using text formating. how can it be my default choice for answering mails?
To set the default spacing:
Another option is to use Styles:
Create a style which includes the spacing settings you like. When writing an email, you can select the text that you want to change style. And then select Format Text > Styles.
I found a link which may be related