When looking at housing for mice two golden rules should be observed: They love to gnaw, so wooden enclosures may not be the right choice, the other rule is that they can squeeze through quite small areas so if you are looking at a wired cage, remember they could squeeze out.
Corners of plastic cages will erode due to the ammonia from the urine, baking soda helps, but eventually you will need to replace the cage I like glass tanks with ledges for them to climb, you can give them a wheel for exercise but remember like most long tailed animals they can trap their tails and very painful injuries may occur.
Good ventilation is necessary and they do need to be clean out on a more regular basis then most other rodents due to their smell, another thing to remember, toilet rolls give as much fun as plastic tunnels, but they can be thrown away at the end of the day and another one place in the cage, whereas the plastic one will need to be washed daily to keep the smell down!
We use shredded cardboard for flooring, it is biodegradable and relatively cheap to purchase, it also act as good thermal in the nest area helping to keep the cold at bay if your mouse has been relegated to the shed or garage! Like most rodents the mouse can be kept outdoors and they can deal with the cold if they have adequate bedding, but they do not do heat! You should place fresh hay for bedding as well as a food source, making sure it has not been contaminated by wild rats or mice or mouldy.
Toys are a great boredom beater for mice and you should supply lots of wooden ones for the to chew, you can purchase so much for mice these days, compared to when I had them, but the toilet roll is still a favourite.
Food is important and you should feed ready prepared mouse food, not hamster or gerbil food. In the wild they would eat, millet, grain and rice, in captivity they could eat most any type of food but care should be taken that they don’t eat the stuff that tastes good but it is not good for them. Oats and dried bread is good for them along with a little fruit and a dog biscuit to gnaw on always goes down well too. Mice can suffer from many illnesses, tumours are quite common and frequently malignant, but the mouse can go on for some time without showing much distress from them but it is always advisable to take them to the vets once found.
Mites, fleas and lice are not common in mice but they can be brought in via bedding and other household pets, so if you should suspect something anti-mite spray for birds is always handy for cleaning out their cages and a visit to the vets for Ivermectin drops. They can be infected with the dwarf tapeworm and the pinworm so signs should be looked for but may be hard to see because adult mice rarely show clinical signs.Respiratory infections can be upper, sneezing face rubbing, or lower, wheezing, weight loss lethargy all or any signs should be reported immediately to a vet.