Ps4 slim gets louder?

So I had the whole normal ps4 which was very loud so very then I sold it and got the slim used but brand new it was very quiet at the beginning but I notice it gets louder over time what can I do so it doesn't get louder becomes?

Take off the top cover (the best thing to do is watch a video) and vacuum out the fan.

So it's best to just clean it all the time?

However, this could void the guarantee.