inductor and switches increase with frequency so there’s a practical limit. With modern parts this limit is around 1 MHz.
Let’s take a simple example based on the circuit in figure 1. Say we have a 12 volt source and we need to supply the load with 5 volts at 0.6 amps. Let’s choose a switching frequency of 300 kHz and assume a ripple current of 33% of the load current. What value inductor is needed? Taking the above equation for ripple current and solving for L we have