Andy,
I asked this question when I was flying in the US. They said that the charts are so cheap that they use coloured pencils and rub the lines out - and once the charts start to tear or become unreadable, they buy new ones. So that's what I did. The chart I used the most lasted around a month.
As for 1/4 mil charts, never tried them over here. But again, in the US, Terminal charts are all 1/4 mil. Caused me to get lost a couple of times when I was on local flights, having not bothered to create a proper plan, "forgot" that I was working on a different scale and ended up having flown twice as far as I thought I had
Fortunately I never bust controlled airspace this way, although it would have been easy to do so. I guess it's just a case of what you're used to.
FFF
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