Why you need a good burr coffee grinder for your espresso shots

I was told time and time again how a good quality burr grinder will improve the espresso shots produced by an espresso machine. I finally listened to the advice and can say that I am impressed with the improvement.
My grinding adventure started a few years ago with the cheapest blade grinder on the market. I quickly discovered that a blade grinder does not really grind; instead it chops and slashes the coffee beans.
The results are some very coarse and unevenly crushed beans which produce under brewed shots as the hot water is just rushing straight through the coffee.
To get a finer grind the grinder has to be run for a longer period. This will generate a lot of heat from the tiny electric motor and this heat can burn the beans in the grinder. Not at all ideal.
While a blade grinder may be enough for drip coffee where consistency is not critical it is not suitable of other types of coffee like plunger, espresso and “Turkish”.
Next step on the grinding ladder was a burr grinder. This type of grinder crushes the beans between a moving wheel and a non-moving part. A finer grind can be achieved my moving the wheel closer to the non-moving part.
The grinder was fairly cheap and from a common high street shop (no names). It improved the espresso shots because the beans were now ground evenly but it was still not great because the grinder was not able to grind finely enough for the powerful Sylvia.
The poor motor of the grinder burned out one fine Sunday morning after only one year of bi-daily usage. It was time to upgrade to a powerful and durable burr grinder.