A method of operating a hearing prosthesis. The hearing prosthesis includes memory and a clock and is configured to deliver stimuli to a user. The method includes determining the stimuli, with the hearing prosthesis, in response to a sound signal and at least in part by using one or more adjustable parameters stored in the memory. The method further includes receiving, from the user, a request to adjust at least one of the parameters, and determining whether to make the requested adjustment by reference to an amount of time, as determined by said clock, or a function based around an amount of time since a predefined event.