Buy for a missing job
Rotation gap checker
Choose the kinds of running you actually do. The checker reads your Shoe Locker and separates covered roles from useful gaps.
A gap is not an instruction to buy. One versatile, comfortable shoe may be enough for several roles.
Your real requirements
What must the rotation do?
Your locker stays on this device. Unknown manual shoes are assessed from the role you assigned.
Rotation audit
Add your current shoes first
Role-by-role result
What to do next
What counts as a meaningful gap?
A role is meaningful only when it appears in your actual week. A road runner does not need a trail shoe because a diagram has an empty box, and a daily trainer can often handle long runs and some faster running.
When a gap matters, use it as a buying brief: surface first, intended use second, then your known preferences. Do not use rotation as a promise of injury prevention.