not enough disk space

I did a search for this but did not come up with a topic already open. Hopefully I did not miss one. One of the stores I manage started getting this error when trying to print pdf/packing slips. I was able to get past this by alllocating more space the the Anonymous ASPNet User account. It was at 100mb and I set it to 200mb. I checked the files/ExportImport/ folder and it only came up to 23mb as far as I could tell but there were alot of pdf's in there. So my question is where was the accoutn disk usage being used up at? Is this an issue where I can avoid this issue programatically? Or simply just keep buying and allocationg disk space?????

purge the files  folder ( and subfolders of unneeded files )

are you saving pictures to database or filesysytem ?

do you have a lot of  images ?

is your maximum image size ( as set in global settings ' media ' tab) very large?

do you frequently edit the 'media'  sizes ? ( doing so will create  extra thumbnails )