I don't believe that is true in the case of ignitors CTG51.
The reason being broil usually gets used much less the bake.
Off hand I can't remember more than 1/2 dozen broil ignitors that I have replaced in the last 10 years.
Bake ignitors a different story, just this last two months I've went thru 9 or 10 of them, which is many more then I normally go thru. I normally only go thru 2 or 3 ignitors a month and usually order at least 4 at a time.
Another good ignitor to carry if you normally like the 5303935066 is the GE WB2X9998, it also comes with the long 17" wires, ceramic wire nuts and also has the dual mounting bracket tabs so it can be used on all the normal ranges like the 5303935066 and can also replace the GE ones where they mount the ignitor on the opposite side of the burner, (so you don't have to mess around with changing the ignitor mounting bracket/cage).