When all is said and done, the final determiner of negative results from breaks in routine’s lies with your individual health condition.
For some, they heal very quickly, for others not so fast. Everyone is different but one thing is consistent. Everyone’s body will activate a healing process that will repair and restore things it finds damaged or stressed beyond normal conditions. That said, taking breaks, depending on the duration of those breaks, will allow the body to fix what it sees as a problem. The 4 phases of the typical healing process of the body will, upon completion, return all structures to original condition except perhaps stronger. Now if you are a slow healer then a one day break in your routine likely wont have an adverse affect but if continued for a period long enough for a healing cycle to complete then your going to experience difficulty continuing with gains. This is just common sense and is dictated by the body.