It's important to listen to your motor. I always start the engine with the radio / car stereo off, the heater or A/C off, any other noise making appliance off (windshield wipers, for example), and listen as it starts up and goes into idle. If it's a completely normal startup and run, then after about 20 seconds or so we can start making noise with other parts of the car. On a cold start, I usually run it in quiet mode for a few minutes ... ideally until the fast idle throttles down to warm idle.
Any abrupt change is cause for investigation. It's much harder to deal with subtle changes over time; we often don't even notice the transformation. Maybe it's just another good use for that video recorder on your cellphone ... do a change, record the sound, there's your point of reference.
You shouldn't really have a situation where the noise increases as the motor oil age increases. Oil changes should be happening long before a noise level increases; the motor should sound the same over the entire oil change interval.