Been using an infrared thermometer for 7 years.
Great for check of tire thread temps, hubs, brake rotors etc.
Distance from object being measured will affect temp (wider vs narrow beam)
I try to hold it 8" from area on each tire/hub so that I can compare the different tires/hubs.
Tire thread....I aim for flat area between threads...two spots
Hubs.....I aim at the transition between drum face and hub and then 2" in from grease cap for two readings
Rotors....on truck I aim just below caliber
Do a quick check at each stop. Sunny side tires/hubs can be higher than shady side. I look for big spread between set on same side.