At home, you probably have batteries, lightbulbs, extra rolls of paper towels and tissues. Lots of things that it just makes sense to have spares of. So when you run out of something, or a lightbulb breaks or burns out, you have replacements available. It makes perfect sense. You'll use it eventually, so why risk not having it when you need it?
The same argument might go for certain supplies in your pharmacy, like receipt paper rolls, statement forms, or labels.
But what about your pharmacy technology? If a hardware component fails, it can be detrimental to your pharmacy operations. However, it's simply not feasible in most cases to have a spare of everything. For one, that's a lot of expense to go to for something that's only a possibility. Secondly, with the inherent complexity and obsolescence of most hardware and software, there's no guarantee that a piece of hardware you buy now will be viable long term. While spare stylus pens, cables, or other heavy use but relatively inexpensive parts might make sense, an extra computer might not.
So what do you do? The answer really lies in the warranty and support you get with your point-of-sale hardware. Make sure your provider can offer you advanced replacement and extended warranty options. Also, make sure they have hardware on hand that they can ship you overnight if it’s an emergency. That way, if you do have a problem with your hardware, and it can't be fixed remotely, it’s an easy process to have replacement hardware sent to quickly. This will ensure your pharmacy gets back up and running as quick as possible.