Most folk on here who haven’t had a factory fitted unit will in all probability have one fitted.
Seeing it’s a regular contributor who makes them, it harsh to be critical but as there’s nothing to criticise I’d get one sorted.
I have to own up to not using one but only because my header tank isn’t standard & the all important water reservoir isn’t where the sensor could read.
Is it Bruce who makes them, I can’t recall.
M