Best practice extending less styles?

I’m just wondering, what’s the best practice when working with less files.

For example: I’m creating a child theme from blank. Now I need to change icon font size of .minicart-wrapper.

 .minicart-wrapper { .lib-dropdown( @_icon-font-size: 22px ); } 

I could either do it in Magento_Checkout/web/css/source/module/_minicart_extend.less (and register this file in (Magento_Checkout/web/css/source/module/_extend.less)

or

I could do it in Magento_Theme/web/css/source/_extend.less

I guess the first apporach is more structured but you have to look through more files.

What’s the best practice?