Let’s say you want to buy a monitor. If you have any option of buying that item later, postpone the decision. For example, if you know you will use the monitor only rarely, and you don’t need too perfect graphics, you could buy a second-hand big monitor. In one or two years, you could sell that monitor, and get some of your money back, and within those years, some new technologies will likely appear.
Or, let’s say you only bought Microsoft keyboards, and you had only problems with them, and you want to try some new stuff. It’s better to buy a second hand Logitech keyboard, see how it goes, and, when you’re happy with the decision, you’ll take a much more informed decision.
Or, let’s say you have the option of buying a cheaper smartphone. You should jump to the occasion of testing the water, buy that smartphone and see how it fits your needs.
Of course, there are counter-arguments. All the examples above are of poorer quality and some of them might break more easily, leaving you without the warranty.
Buying second-hand implies some risks.
Yes, you will get a better monitor and smartphone two years from now, but what will you do during those years? Will you be as happy with the second-hand item as you would have been with the new item?
Anyhow, if you can postpone a technology item for some years, it’s likely you’ll be able to get a better deal in future years.
It’s just that the wait is not so pleasant. :)