Mauro, if we understand bleeding the system as getting rid of air from it - yes, this necessity will always appear after any sort of work with pads, discs or hoses replacement. Or almost always.
If you mean draining the brake fluid - it is not always necessary. Although when replacing hoses, in my limited experience, I think it may be difficult to avoid it.
But also: we should be simply replacing brake fluid with new one, say, every 2 years. This is because brake fluid is higroscopic, so it absorbs water from air. Once it has too much water, it may be boiling in high temperature. Boiling means evaporating and gas or vapours is something we cannot have in the brakes system, as it will not be able to build pressure necessary to brake as gasses are squeezable (liquids are not).
So if you have not replaced brake fluid in your car, recently, this would be a good occasion to do it.