1. A method comprising: executing, by one or more computer processors, a software program, the software program requiring one or more physical interactions with a user through an input/output (I/O) device, wherein each of the one or more physical interactions includes respective predefined dimensions indicating a proficiency in performing one of the one or more physical interactions; tracking, by the one or more computer processors, the one or more physical interactions; generating, by the one or more computer processors, a familiarity profile for each of the one or more physical interactions based on the respective predefined dimensions for each of the one or more physical interactions, wherein the familiarity profiles include user input, help usage, error recovery, task completion, and tutorial completion; applying, by the one or more computer processors, a weighting parameter to the familiarity profile for each of the one or more physical interactions to generate an overall familiarity metric indicating an overall proficiency with the software program, a related software program, and an extent of customization for the software program; customizing, by the one or more computer processors, the software program based on the familiarity profile for each of the one or more physical interactions; executing, by the one or more computer processors, a second software program, the second software program requiring one or more physical interactions with the user through the I/O device; determining, by the one or more computer processors, whether the second software program is related to the first software program; and responsive to determining that the second software program is related to the software program, customizing, by the one or more computer processors, the second software program based on the familiarity profile for each of the one or more physical interactions for the software program.