You would notice it the day after for a minute or so, as your fingers would be a bit slower on the uptake, but only missing a day occaisionally isn't going to really affect your playing though. If it takes you two months to get up to a certain tempo with an exercise, and you stop playing it and lose the tempo, it will only take you half the time(if that) to get back up to speed. However, it is better to practise every day for one hour than once every three days for three hours. Consistency is more important than volume generally, as it keeps your fingers supple and constantly improving.