I only put the clothing on if we're going to be outside a while.... like at the dog park, or for a walk. She goes out naked for potty breaks or if we're playing in the yard for a little bit. She gets booties at the dog park, and on walks depending on how icy/slushy the roads are.... but only because her paws bleed after being in the snow for a while. Otherwise I don't think they're necessary, her booties are thin and wouldn't keep her paws warm, but they prevent any irritation.
I've just started having her wear her fleece on walks, and it's been in the 30s/40s. Basically, if I'm bundling up and wearing a winter jacket and a hat/gloves, then I assume that Juno would probably be more comfortable in a jacket. Especially when it's windy/rainy/snowy.