How do you know when a wood fired oven is hot enough?

Some people use thermocouples and digital thermometers or infa red scanning thermometers. Me, I’m old school and like to keep things simple!
When you light the fire the bricks go black from the soot. When the oven has reached temparature they turn white again and piece of wood catches fire instantly. I tend to keep it burning that hot for 30mins if I’m cooking for lots of people (say 30 pizzas) and 10 mins or so for the family.

Not ready

Not ready

Ready!

Ready!