Joined: Aug 2010
Posts: 12,728
Likes: 2,105
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
Some people will have their rain gear in a rear pannier, or sun screen, or chain lube, or dozens of other things.
When you come out of a grocery store, that is a common time to open up the rear panniers to refill them. But I usually just put groceries in the rack top bag.