Randomness from a CSPRNG (cryptographically-secure random number generator) never really gets "depleted," since as long as the seed contains enough entropy and

Randomness from a CSPRNG (cryptographically-secure random number generator) never really gets "depleted," since as long as the seed contains enough entropy and isn't compromised, then it's computationally infeasible to learn anything about the internal state of the CSPRNG from it's outputs. See https://research.nccgroup.com/2019/12/19/on-linuxs-random-number-generation https://research.nccgroup.com/2019/12/19/on-linuxs-random-nu... for a nice overview. The Linux random number generator did used to have a notion of entropy depletion, but that is no longer the case (at least for x86-64 systems: https://wiki.archlinux.org/title/Random_number_generation https://wiki.archlinux.org/title/Random_number_generation). On older systems that have a notion of entropy depletion, you would eventually deplete the entropy counter and /dev/random would start blocking if you aren't feeding new entropy into the system.