Combine two almost identical sidebar templates, used for blog index and category index pages
You could pass the content to the sidebar include, as follows:

{% include 'sidebar-template' with {
    content: entry.sidebarContent
} only %}


The sidebar template would then use content, rather than entry.sidebarContent.

It's also worth taking a look at Twig embeds, which can be very useful in situations such as this.