We recommend models equipped with external side pockets, especially if you're the sort of person who's always searching for your essential items at the bottom of your bag (lip balm, keys, smartphone or cigarettes, for example). Opt for pockets that can be closed such as those on the Minimalist from Mission Workshop, especially if there are many speed bumps on the road, or if you live in a region where it rains 345 days a year. Do you need to carry your bicycle lock?