As a file size optimization, Inkscape does not write into SVG some of the stroke properties if the object has stroke:none and some of the fill properties when it has fill:none. The only situation where this might affect you is if you remove stroke from an object and then turn it back on - the object will get the default stroke instead of the same as it had before.

Also, in manually-edited SVG where a parent group has no stroke but sets some stroke properties to be inherited by its descendants, you will need to set stroke property to other than none on the group, and suppress inheritance with stroke:none on those children that don't need it.

Specifically, if stroke:none, the following properties do not get written to SVG:

stroke-width stroke-linecap stroke-linejoin stroke-miterlimit stroke-opacity stroke-dasharray stroke-dashoffset

Note that this does not include marker properties, which means you can still have markers on a path without visible stroke.

If fill:none, the following properties do not get written to SVG:

fill-opacity fill-rule