Optical Encoder Max Speed

I was just wondering what a safe max speed is for the encoders was. I looked at the encoder’s page and I could not find any specs on it regarding a max speed. Also at what point do the encoders stop accurately measuring rpm/ ticks.
thanks for the help.

See this thread.

how-fast-can-a-quad-encoder-detect-movement

It’s really limited by mechanical aspects rather than the firmware.