It's a general rule to buy the largest cage you can afford.
In the beginning you can find it big, but when you put a wheel, water bottle, shavings and toys it might turn out the cage is not so spacious. If the hamster doesn't have enough space to exercise, he can develop cage paralysis

How often the hamster cage should be cleaned?

It depends on the type of cage you have and the number of animals you breed in it. You'd better have one Syrian in a cage, unless they are met as youngs and are accustomed to each other. As for the dwarfs - you can put two and more in one habitat. The cleaning rule is - when you begin to feel the smell from the cage - it should be cleaned, it's about once a week. Wire frame cages due to their good ventilation need to be cleaned less often than those with tubes.

Hamsters are clean animals and prefer to have a clean cage. The smell that comes out of the cage is usually caused by dirty bedding rather than the hamster himself. It is therefore
recommended to change it once a week and clean all the parts of the cage (tubes, tray, wheel, water bottle and bowl) with hot water and soap (dry it well before you put the new bedding). Your hamster will thank you with a happy game in the clean cage

Is it permissible to use a second-hand cage?

Yes, you can use, although it is not very advisable, because the previous animal might have died of a contagious disease that can be transferred to your pet, too. Anyway, if you have decided you have to disinfect it very well. 

Home made hamster cages?

This is the most economical way to grow a hamster. You can buy a plastic container and
cover the pot with a net (be sure that the distance between the bars is narrow enough). Of course, here again appears the disadvantages of the plastic aquarium.
 
Furniture for the hamster cage?
 
• Bedding material – the best option are the shavings which can be found in the most stores. It's important the material not to be the finest because it might choke or injure the eyeball of the hamster and caused his blindness. Scented bedding is also not recommended for the risk of wounding the sense of smell and the nasal channels of the hamster or the rodent. The perfect bedding is the non-toxic Aspen. Avoid the CEDAR bedding at all cost since the hamster is allergic to the resin in it. The bedding is an important factor because it approaches the hamster or rodent to its natural environment where he used to nest and hide. Another option is to provide the hamster with toilet paper or paper for printers that can also serve him to make a nest. Just cut it into small pieces to make it convenient for the animal!
• Water bottle and bowls are often included in the hamster cage
• Toys can be limited to exercise wheel which is included in the most cages and tubes - and yet hamster is not a dog.   
• It's good to put a bowl with sand in the cage in which the hamsters can make sand baths, as if they are still in the desert. This can lead to more frequent cleaning of the cage, but in return you will have a healthy and good looking, clean hamster. Wheels are important for the rodents in order to maintain their shape. Contusions are not excluded but we are proud to announce that our wheels are save to the limit.

What else is needed for the proper breeding of your pet: It is a mandatory to cover the floor of the cage with shavings which most feel closer to the hamster habitat. We recommend to change them once a week. Most of our hamster cages have a built wheel and we highly recommend you to have your pet's toys fixed in the cage. Our long experience with small animals and their owners has showed that buying separate balls, wheels, hideaways etc. could lead to two possible situations: if you buy a hamster cage separate from other accessorieis it is very difficult to guess the right sizes of the toys and they won't fit properly inside or even if they look fine, their free moving in the cage makes them unappropriate for their initial purpose. The result from both of the situations is that your hamster will wonder what are these strange things in his home and won't play in or with them at all and moreover you will realize that you have made your money fly. Having such an accessory for your rodent is a must because most of them have a huge amount of energy, which have to be used up. But if it is not fixed properly which can be made only if it is designed for a particular cage, sometimes these supplements could result in serious injuries.
   The same is the issue with the water bottles and feeding dishes - if you just put some bowl in the cage, its content will immediately spill or scatter if the dishes are not adjusted to the walls or have some special place designed for them. You should't forget that all these things have to make the life of your hamster easier, not harder.