The HODLER program will reach its saturation point when the relation between the number of sensors participating and the daily bonus budget available doesn’t allow for the maximum amount of PLANETS per share held (38 PLANETS) to be distributed.
From that moment on, the number of PLANETS each share is worth will decrease by a fraction depending on every additional participation (more stakers, less rewards for each).
So, the sooner you join the HODLER program, the longer you will collect the maximum amount of PLANETS per share held (given that you stick to all the requirements and remain eligible).