Do I need to get my TPMS done when I change tires?

I am putting four new tires on my wife's 2010 Toyota Yaris. Firestone said they'd install for $75, but when I got there they also wanted about $40 to (something) the TPMS on each tire (they made it sound like servicing each one, said the sensor could stop working otherwise).

Is it a real possibility or is this a stupid tax?