I am guessing not enough people have asked for this or needed this before for it to be implemented, and although the logic may look simple ("avoid conflicts with 'Holiday' category", for example), it may introduce other bugs or complexity.

The time it took me to research and write this (~15 m.) is probably more that it will take it to do it every year, manually.

So, this is not possible automatically in Thunderbird, however this is how I would go about it.

Taking into account/assuming the following:

• Bank payments typically take 2-3 days to clear.
• You have already manually loaded a public holidays calendar in Thunderbird
• Thunderbird recurring events dialog can't notice if an appointment is a public holiday or not

I would then create events with these caracteristics specified in the recurring events dialog under Repeat > Custom when creating a new event):

• Repeat monthly
• Every 1 month
• The last Tuesday (to account for 3 business days transaction time)
• Range of recurrence: Create 12 Appointments

This would cover 12 bank payment scheduled appointments.

For safety, I would then also create another appointment on the 11th month to be reminded to schedule another 12 appointments.

I would then visually check for any exceptions or problems, correct as needed.

Thank you, Fabian. I can imagine that, at first sight this sounds quite complex to implement - which is why I gave an idea of how it might be implemented in my second paragraph. All that needs to be implemented is an editable "excluded date" list - with optional presets such as "every Saturday" and "every Sunday" and two other, exclusive, options called "use day before" and "use day after" It would then be the users' responsibility to edit in any extra days, such as public holidays. To me, that would be a really useful improvement - as "every month" and "every 2nd Wednesday" just doesn't reflect the real world. I'd expect that a lot of folk would welcome, and use, this facility.

Thank you for your outline solution. Bank payments here in the UK are typically instantaneous, so making a series of cleared payments - including payments that rely on previous payments - can all be done at the rate of about 12 per hour.

I looked at Repeat>Custom, but could find no days-specific way of aligning the repeating to, say, the 26th. The "third Tuesday" idea you mention does not give the precision I need.

Perhaps my analysis of the change required may enourage Lightning's authors to try and implement this feature. In the mean time, the only solution I can see is to set single events month by month - and include in the Event Title the text "SET UP NEXT MONTH'S EVENT - *THEN* CARRY OUT THE BANKING TRANSACTIONS!!!".

Thank you, I understand this is something that many Thunderbird + Lightning users may appreciate. It wouldn't be implementend in Thunderbird, though, this would be something specific to the Lightning extension.

I've asked how/where to best make such suggestions to improve Lightning, you can follow up that link to see any future answers.