Every other week lessons are a good deal for families and a quiet source of double bookings for schedulers. The fix is a small, strict model that every slot follows.
A weekly lesson occupies a slot every week. An every-other-week lesson occupies it half the time, which means the slot is free half the time and a second student can use it. That is the whole appeal: a teacher can serve twice as many families in the same hours, and a family that cannot afford or fit a weekly lesson can still take one.
The trouble is that a calendar with no concept of "which week" shows the slot as taken, or worse, shows two lessons stacked on the same time with no warning. Double bookings appear when somebody adds a second student to a slot without knowing the first one is weekly, or when the week label is kept in a person's head instead of in the schedule.
Give every lesson exactly one of three values. A means it happens in A weeks only. B means it happens in B weeks only. Both means it happens every week. Then define the weeks: week one of the season is an A week, week two is a B week, and they alternate from there. Write the calendar dates of the first A week and first B week into the schedule so nobody has to count.
With that model a conflict has an exact definition. Two lessons for the same teacher at overlapping times conflict only if their week values overlap. A and B never conflict with each other. Both conflicts with A, with B, and with another Both. That one sentence is the entire rule, and any tool or spreadsheet you use must enforce it the same way.
The cleanest A/B pairs are two students of the same instrument and similar level with the same open window, because the teacher's materials and prep are shared. But the pair does not have to match in level. What matters is that both families agree to the same weekday and time, and that each of them is told which week is theirs.
Never promise a family "every other week" without naming the week. "Your next lesson is Tuesday, October 13, then every second Tuesday after that" is a complete sentence. "Biweekly" is not, because half the people reading it will assume the other half.
Say a guitar teacher has Tuesday at 4:00 for thirty minutes. Dana is a weekly student, so her lesson is Both and the slot is full. If a new family wants every other week, the slot cannot take them. Now suppose Dana moves to every other week. Her lesson becomes A. The Tuesday 4:00 slot is now half empty, and a B-week student can take it with no change to anything else on the board.
The same logic shows why converting a weekly student to alternating is sometimes the cheapest way to open a slot for a new family. You do not need a new time, only a second family who wants the opposite weeks.
The less obvious problem is balance. If most of your alternating students land on A weeks, teachers have heavy A weeks and light B weeks, and their pay and fatigue swing every other week. Count lessons per teacher per week type as you place. Aim for the A and B totals to be close, and when you have a choice between two equal slots, take the one that evens them out.
The same applies to the longest day. A teacher's Tuesday can be fine in a B week and overloaded in an A week. Check each day in each week context separately. A day's load is the larger of its A-week version and its B-week version, never the two added together.
Families with two children often want both kids on the same day and teacher. With alternating weeks you have two good options. Put both children on the same week so the family has one lesson trip every other week, or put them on opposite weeks so there is a trip every week with one child. Ask which the family prefers, because it depends on how much they value a free week versus a steady routine.
When a holiday cancels a Tuesday, the A/B pattern should not shift. Keep the week labels tied to calendar dates and let the cancelled lesson simply not happen. A common failure is "re-starting the count" after a break, which silently swaps who is A and who is B and puts two families in the same slot on the same day.
For make-ups, treat the make-up as a one-off lesson with its own date. Check it against the teacher's calendar for that specific date, not against the recurring pattern.
Run these checks on any schedule that includes alternating lessons. They take minutes in a tool that understands weeks and a long afternoon in a spreadsheet that does not.
This is exactly the sort of rule that is easy to state and tedious to enforce by hand across a hundred students. Set the Tune treats A, B, and both as first class values, checks conflicts per week context, and balances load across the two weeks. The write-up on alternating week lessons goes through the product side, and the demo shows a real schedule.
Yes, if one is on A weeks and the other is on B weeks with the same teacher, day, and time. The slot is used every week but by a different family each time.
It is ambiguous. It can mean every two weeks or twice a week. Use "every other week" and name the actual dates of the first lesson so there is no confusion.
Count each teacher's lessons per week type while you place students, and prefer the slot that brings the A and B totals closer together.
They should not. Tie the weeks to calendar dates, let the holiday lesson be skipped, and do not restart the count after a break.