Sweater vests: what are they good for?

Dear users, dear authors,
What are sweater vests used for? 

Slipovers are very practical right now during the transition between seasons, especially for kids. They don’t feel like they’re bundled up too heavily, but their torso still stays warm. My granddaughter loves her slipover—it’s coming in handy now when she’s playing outside—

I like sleeveless sweaters, too. They keep your back warm while the rest is pretty breezy. And you can see more of the blouse I’m wearing underneath

I knitted this slipover a looooong time ago. And I still love wearing it.