Silica gel will turn from blue to pink when it absorbs water.
When the dry box is closed, the moisture from the air inside will be absorbed.
When the dry box is opened, the inside air mixes with the outside air and when closed, the cycle repeats.
This cycle will go on until the silica gel turns pink - it can no longer absorbs any moisture.
The generally accepted humidity norm to inhibit fungus growth is around 50% RH.
Looking at the effort you would need to change and/or dry silica gel, it may be wiser to spring for a dry cabinet instead. Yes a dry cabinet may cost more upfront and require constant electricity supply but it offers more convenience over the long run than a dry box.
It ultimately depends on how much you value convenience compared to others. Alternatively you may choose to go with a dry box first, and when you have more equipment or simply want a better product, then upgrade to a dry cabinet. That is perfectly fine too. I believe most people who have posted here earlier are speaking from experience.
Drybox is useful for keeping things for long term without opening regularly- example maybe once or twice a month or less regular. If you keep opening the box, the silica gel will need to be reactivated very regularly - especially in our humid climate. I don't like the hassle of recharging the silica gel. When you forget to do so the dry box becomes ineffective. I bought my dry cabinet more than 7 years ago and it is still working (fingers crossed). It's large enough to store my small collection of lens and bodies and I am convince the $ spent was worth it. Before this, my lens and accessories were all affected by fungus.
If you are thinking long term and you have spent quite a lot on your camera, then a dry cabinet is the way to go. If you just have a point and shoot, then maybe a drybox may suffice. Spending more buys you convenience and peace of mind.
A small dry box would probably cost about $35 to $50
while a small dry cabinet would cost about $100++ ($12X for digi cabi 036)
For the dry box, you will need to monitor on a regular basis to check that the humidity is within acceptable range. When the silica gel turns color (depending on how frequent you open the box, it can last 1 week or 2 week), after which you will have to change it (or do the microwave thingy which I know some people have done) then repeat this process.
For the cabinet, once I've get it into the humidity range (it will settle down within a few days), I never have to touch those knobs again.
a used dry cabinet is slightly less than a hundred, unless you able to buy a 2nd hand dry box at $15 or $20, or manage to get a hand me down drybox, I don't see how much money can you save.
like many members already said before, unless you able to keep a good habit of checking drybox and maintaining the Silica gel regularly, don't you think trying not to open the dry cabinet more frequently, will make you use your camera lesser, isn't counter productive to own a camera this way?
Base on your post history, you didn't use drybox or dry cabinet when you bought your camera initially, and from your another thread, your lens already infest with fungus. FYI, fungus lens cleaning is around $120, if you already own a dry cabinet long ago, that shouldn't happen, this a valuable lesson for you to learn.
penny wise pound foolish, or enjoy your camera to the fullness, the choice is yours