dear xin and myin,
chyeo is right. Always use a hygrometer to measure the humidity to make sure. Should not try guessing. Invest in one, you will need it very often. Even if you have a dry box, you will need to double check sometimes to make sure that the one on the dry box is working. Mine was actualy konk out. I didnt know until I double checked it with a known working hygrometer.
Not just cameras, if you have large amounts of negatives, slides, etc, you should keep them in a dry box too if you intend to preserve them. Fungi grow on negs and slides too. Worst thing is that for negs and slides, there is no way of removing them.
We live in a horrible climate. Reason why those camera shops can leave their stocks on the shelves all the time is that the shops are usually air-con, which is dry, and hopefully the cams and lenses don't sit on the shelf for too long.