Plan a Sinking Fund for One Predictable Annual Cost

Car insurance, an annual subscription, or a yearly bill always lands like a shock despite happening every year without fail. This works out the simple monthly amount that would cover it comfortably by the due date, plus a suggestion for keeping that money somewhere it will not quietly get spent on something else.

One cost comes round every year and always feels like a surprise, even though it never actually is. Name [the annual cost and roughly when it falls due], and get back a simple monthly saving figure that would cover it by the due date, plus one suggestion for where to keep that money so it is not accidentally spent on something else.