If you work on the principle that a reduction in oil pressure at idle speed is equal to a reduction in oil level, then the chances are that you will incur serious engine wear/damage before you are aware of the need to top up
I check my oil every weekend because as I have mentioned in other threads, mine is using it at a rate of about 0.5 litres per 1000 miles I've therefore had plenty of practice at dipping the oil and it gets easier the more you do it.