Even? /60 should be the minimum, even home users usually have a couple subnets (guest networks for example, sometimes one for the router's WAN link) and you want the boundary to be on a nybble boundary
Yeah, it's not always, but for most home networks it probably is. Ideally they'd give you a /56 or even a /48, but giving those on request and a /60 by default is fine.
