The performance load of an object is how mentally and physically easy it is to use. Here are some examples of the performance load from everyday items from my life.
Example 1: Broom
This is an obvious example of performance load changing how commonly an item is used. Since the creation of the much less physically intensive vacuum cleaner the broom is used much less often.
Example 2: Simple Weather Station
Rather than going out to set up and read something like a rain gauge, this weather station sends its automatic information to a screen in another location. The job is much easier and so likely to be used by at home weather men.
Example 3: Peeler
A peeler as simple as this one requires little cognitive load, especially compared to something like a knife. They are commonplace in kitchens for such a reason.