Every internal combustion engine consumes a small amount of oil. With each of its millions of strokes, this is simply a given for lubrication purposes. However, the amount is extremely small. (This is not to be confused with oil loss, which seeps out of the engine's crevices.)
However, water condensate accumulates in the engine oil, causing its volume to increase slightly. This often occurs with frequent short trips and when the engine is running at low temperatures (oil sump below 90°C). Consequently, the dipstick reading may not be lower, and it can mistakenly appear as if the engine hasn't used any oil at all.
This is easily noticeable when changing the oil after a long period of inactivity, as the first few shots of water will be present in the oil. Therefore, it is advisable to change the oil more frequently, especially with low mileage or short trips.