A box of Indian sweets can contain items that will be fine in a week and items that should be eaten the same day. The dividing line is how much water in each sweet is available.
Available water is the governing variable
Microbial growth needs water that is free to participate in biological processes, not merely water that is physically present in the food.
Sugar and salt bind water, and fat excludes it, so a sweet can feel moist while offering very little usable water to anything trying to grow in it.
This is why a syrup-soaked sweet, which is visibly wet, outlasts a fresh dairy sweet that feels comparatively dry to the touch.
Fresh dairy sweets sit at the vulnerable end
Sweets built on drained curd or lightly reduced milk carry protein, moisture and moderate sugar, which is close to an ideal growth medium.
They are made for immediate sale, kept chilled, and are the items a shop discounts as closing approaches rather than holding overnight.
Because the safe window depends on temperature and handling throughout, published food safety guidance is the right reference rather than any rule about days.
Dry and fried sweets sit at the stable end
Sweets built on roasted flour, nuts and ghee contain very little free water, and the fat coating each particle further limits what is available.
Their failure mode is not spoilage but staleness and rancidity, as the fat oxidizes over weeks and the texture hardens.
Airtight storage away from heat and light slows both, which is why these are the sweets that get posted, gifted and carried on journeys.
Syrup provides its own protection
Sweets held in concentrated syrup are protected by the sugar concentration surrounding them, on the same principle as a preserve.
They still need refrigeration once the syrup is diluted by the sweet absorbing it, and the container has to be kept clean and closed.
Their quality declines by absorbing too much syrup and turning heavy, which is a texture problem rather than a safety one.
Planning a box around the gradient
A practical order of eating runs from the fresh dairy items first, through the syrup sweets, to the dry and fried ones last.
Storing them together in one box shortens the life of the dry items, since moisture migrates from the wet sweets into them and softens the texture.
Separating the categories on arrival is the single most useful thing a household can do with a large mixed box, and it costs nothing but two containers.