I've only used a 1/2 mil chart, and never found the need to get a 1/4 mil, even for local bimbles. If I'm carrying passengers I normally take up some OS maps of the local area, they always seem to enjoy following our progress using those whilst I'm using my 1/2 mil. It's very useful if we're looking for a particular road or house - when we are within a couple of miles the OS maps' larger scale becomes very useful, and the passengers enjoy navigating us towards their house.