Players go through several development cycles throughout the season. They typically occur a consistent number of days apart.
However, significant transactions can adjust this schedule. For instance, if a player is traded, claimed off waivers, promoted or demoted at a time that is pretty close to when they would have had a development cycle, they will go through a development cycle immediately. This takes the place of their regularly scheduled development cycle. Their next one will then occur sooner than typical.
It's setup this way so everyone will go through approximately the same number of development/aging cycles but each dev cycle is tied to the coaching and training and medical staff of the team the player was with at the time of the cycle.