tashiha, usually when new brought drybox needs at least 2 days to stabilized. also, check if ur drybox is directly in front of the airconditioning, and leave "Space" behind the drybox for air circulation for 'bringing away moisture' from the 'dehumid unit'

if this go on for a week, consult ur dealer.

jagged, makoshark, like kmarc said, there is no DATA for it. but, recently, i DID heard a lot of that issue, it seem today, camera are affordable and people buy and becomes a Passive shooter (camera stored for 2-3 weeks to months). and yea, base on my theory (my opinion, some might differ) yea, leaving it too long will 'suck dry' the plastic.

leaving a wet sponge is big No. if ur thristy hippo already filled up, u are adding More moist inside, which favor spore to grow.

opening it 2-3 days is Good. but if u do not have the time, then (read #)

leaving it open or not tightly close is also another issue, too much moist in rainy day. and u might forgotten ur silica might filled up quickly then u thinks.(read#)

# read this: from one of my experienced friend (using this technique for more then a year) is to POP several small needle hole on the container (dont use tupperware, ur mum will kill u) so it can breathe... but downside, u have to check ur silica every week, to see if it filled up with moist and change(or cook it) when necessary.

anyhow, in all other method u can DIY, get a drybox. there is small drybox enough for a camera body and 4 lens and a flash, only around rm300. i think its the 12-15L model