I fitted a scan gauge because the oem temp gauge is pants. Took about 5 mins to fit. I have velcro'd it to the controls under the stereo, the windows, door lock, etc, etc.
Now I know the exact temp of the coolant and in sitting traffic you know when the low speed fan kicks in. You never actually reach 106 degrees, when the fan is designed to kick in, because as soon as the fan kicks in it drops like a countdown timer to high nineties.
Peace of mind, after one blown head gasket and one new cylinder head.
Oh, I also fitted an aftermarket low speed fan resistor as mine had failed, like many others. Cost about £4.79 instead of the quoted £400 to replace the fan.