There is a particular category of risk in small businesses that is invisible precisely because nothing is going wrong. A piece of software - an operating system on the machine in the back office, an old version of an accounts package, a till system, a design program, a database somebody built years ago - has passed the point at which its maker supports it. It did not stop working that day. It works exactly as it did the week before, it does the job it was bought for, and everybody who uses it is happy with it. That is the whole difficulty: there is no symptom, no error, no prompt, nothing that would cause anyone to look at it.
What ends at the support date is not function but repair. Flaws keep being found in software after it stops being supported - that is normal and expected, since people keep looking - but they no longer get fixed. The gap between what is publicly known about a program's weaknesses and what has been corrected in it widens steadily from that day onward, and it never narrows again. So the risk of running it does not stay constant; it increases quietly and continuously while the experience of using it remains identical. This is the opposite of how most risks behave, and it is why intuition is a poor guide here.
There is usually a second-order problem too, and it tends to be the one that actually forces the issue. Unsupported software eventually stops working with everything around it. A browser it needs is no longer available. A bank changes how its site works and the old version cannot connect. A file arrives in a format it cannot open. A new printer has no driver for it. Each of these is a small breakage, none is an emergency, but together they arrive at an accelerating pace, and they usually arrive in the middle of something else. The unplanned migration, done urgently and badly, is almost always more expensive and more disruptive than the planned one would have been.
The manageable version of this is simply to know. Once a year, list the software the business genuinely depends on, and check whether each item is still supported - the maker publishes this and it takes minutes per item. Most will be fine. The one or two that are not become a decision to be made calmly, with time to choose a replacement, move the data, and train people in a quiet week. That is an entirely different proposition from discovering it on a Monday when the thing has stopped connecting to the bank. Nothing about this is urgent, which is why the annual habit matters more than any single check: the risk grows continuously and only ever becomes visible all at once.