You should look at the requirement for accuracy. You may need many pulses per revolution.
When travelling fast, you can count the number of pulses in a certain time, you will need a lot of pulses.
When travelling slow, you will need to measure the time between pulses.
When travelling fast, you can count the number of pulses in a certain time, you will need a lot of pulses.
When travelling slow, you will need to measure the time between pulses.