Were you also taught to use a PCR holding temperature of 4°C to keep your samples in good shape after the PCR reaction is finished? You know -- after the many cycles are done, but before you take your samples out of the machine?
You don´t actually need 4°C to store your samples safely -- not even when you leave them in the machine overnight.
DNA is extremely stable -- and potential nucleases are deactivated by the high temperatures during the PCR cycles.
So if not 4°C, then what?
Well, some people use 10°C, others 15°C, and there are even scientists out there who are using 20°C as their PCR holding temperature. And they don´t see any significant loss of sample by doing so.
Using a higher temperature means less energy consumption and less strain on the thermal block. That translates into fewer issues that need repair and a significantly longer lifespan of the PCR machine.
That´s good news for you, your boss and the planet!
If you are not comfortable with going directly from 4°C to 20°C, maybe you can try a holding temperature of 10°C next time you're doing PCR just to see if your nerves can handle it. And who knows -- maybe with time, you will feel just fine using 20°C.
Warmer holding temperatures are not only appropriate for shorter times -- they actually have the largest positive impact on the planet and the PCR machine when using them overnight.