I carry this on centuries or longer rides, using it at the half-way point, as it seems no matter how much chamois cream I used at the start of a ride/race, it is gone by the half-way point. The 0.3 oz size is just right. When travelling I also carry some in just in case I leave my large container of chamois cream at home (which has happened a bunch of times); or as I did this summer, loan to a friend that had no chamois cream.
The Paceline Chamois ButtR singles are perfect for long rides where multiple applications are necessary to keep you comfortable. Stick a couple in your jersey pocket or saddle bag for comfort on the go!