Bit late but every 4 weeks I remove the old one and put a new disk freshner in. I get them from Home Bargains when I go. Usually get two packs, gave one to my grandad when I first got them so has used a entire packet in one week - one for my DC14, one for my DC04, one for my grandads DC04, plus two spare for him and one for my dc07, 6 in a pack. Ive always used Spring Meadow, but today I bought some summer meadow.
I got 5 spring meadow left and 6 summer meadow.
but I been using freshners for weeks now without problems, i used to put them ontop of the filter but they werent very good there so now I put them ontop of the motor diffuser on dc14/07 and next to the diffuser on dc04's