and I totally disagree with the theory to poke a new hole every time to check.
here's why:
stuff like chicken breast has a thick part and thinner parts.
all kinds of beef / lamb / venison / turkey cuts have thicker and thinner parts.
if you check the temp 'somewhere else' you have no idea how much the temperature has changed since the initial check . . .
depending on how hot you roast, on a simple chicken breast you'll see 15-20 degrees (F - half that in C) from thick end to thin end.
for precisely this reason I slice those megasaurus chicken breasts longitudinally into two slices of equal thickness: