Here is the scene: a course on the new till system on Thursday morning, four seats, six people on staff. Two stay behind to keep the store open. Nothing unusual so far. The real question is how those two get picked, because the team absolutely notices. If the same people always stay, the message that lands is not "we trust you with the store". It is "training is for the others".
And since training opportunities in retail are rare, every exclusion counts double.
Coverage is not a consolation prize
Start from the flip side: whoever stays that day holds up the service alone or nearly so, usually with more customers per head and without the experienced colleague to lean on. It is a harder shift than usual, not a less important one. Treating it that way changes everything: say it out loud, avoid stacking that same day with deliveries and restocking, and consider giving something back (first pick of shifts the following week, for instance).
The single worst criterion is "whoever complains least stays". It works once. Then the easy-going person stops being easy-going, or worse, stops telling you what they think.
Rotate, and keep track
The healthy rule is simple: each training round, different people stay behind. Actually applying it requires knowing who stayed last time, and this is where memory fails. A note in the shift plan (even just "covered store during course X") turns rotation from a good intention into a checkable fact.
If a course genuinely cannot be missed by anyone, there is almost always an alternative: two shorter sessions on different days, or a closed-door slot if your volume allows it. It costs a little extra organisation and saves you the first-class and second-class citizens effect.
Whoever stays needs to know who to call
A detail that often gets forgotten: on course day, the people left in the store also lose their usual points of reference. The manager is in class with their phone on silent, and so is the experienced colleague. Before leaving, write down three things: who to contact for genuine emergencies, what can wait until 2pm, and where to find the two or three items that always matter at the worst moment (stockroom keys, returns forms, the card terminal support number).
And whoever goes to class should actually be there
Last point, the mirror image: training interrupted every ten minutes by calls from the store is not training. If coverage is properly organised, the people in class can afford not to answer. If whoever stayed was left to sink or swim, the calls will come, and you will have paid for a course that half the room only half followed.
It helps to have a shift plan where training absences show up like any other commitment, with cover decided in advance and visible to everyone. That is exactly the kind of day Sked Solve was built for, and the site shows how it handles it.