When the weather is cold, give some absorbent cotton to keep warm and absorb water. Don't catch a cold from rayon unless you absorb water. Drugstores sell very cheaply.

When the weather gets warmer, you can give some shredded green toilet paper or paper towels, because hamsters will eat the paper into their cheek pouches and bring it back to their nests for plastic surgery. If it is unqualified toilet paper, additives such as bleach will kill rats.

You can give cat litter in summer, which can cool off the heat. It's worth ten yuan and several kilograms.