Extrusion multiplier value
Printer hardware and firmware settings like:
Type of extruder and steps per mm value
Z axis movement: threaded rod, lead screw size and steps per mm value.
Type of stepper and drivers.
For example a M5 threaded rod with an standard 1.8 deg stepper motor and A4988 driver in theory needs 4000 steps per mm but in reality might go up to like 4040 or under like 3995, if your steps are not set correctly your next 0.3 layer might be only at 0.25 or even less and soon enough the nozzle will be dragging on the part, same with e steps etc, etc.
So, have you done all the calibrations needed? Have you changed any hardware or any settings in the firmware lately?