General information
(the links below take you to each different section)
Lifespan
Hedgehogs can live anything from 3-6years, however, breeding is said to decrease the life of a female, especially if she is over-bred, but it is not known by how much, some have know healthy breeding females to live for as long as a non-breeding female, so it appears to be down to personal experience and the individual hedgehog and how much she is bred and how well she is kept.
Lifestyle
They can not under any circumstances live outside. They require a constant temperature, this is because they will hibernate at lower temperatures and could run the risk of dying. There is some debate as to how warm they have to be, and information ranges from 18oc to 24oc with a low humidity level, I have found that both my hedgies do fine at 20oc and sometimes lower as long as they have a heat source in the cage if it does get cooler (personally I have found the "Snuggle safe" heat pad to be perfect) I put it in a corner of the cage and they can either move off or onto it as they please, it must be monitored, as hedgies can burn themselves if they spend too much time on the heat source, or can't get off it. There is need to be sure that the temperature is high enough as these little hogs could not survive hibernation like the wild ones do.
Hedgehogs are nocturnal by nature and they need at least 12 hours of light (artificial or real) a day so that they do not think it is winter and try to hibernate, however this is different for differnt people's experiences.

Some requirements
Hedgehogs also have some general requirements, they need their nails cutting often as they grow quite fast and can sometimes curl under and into their toes, this can be painful. They also run through their own poo in their wheels, so need their toes cleaning out often, otherwise this can lead to infections, esp if they have long nails or cut feet. Sometimes (especially during quilling1) they may need a bath, some like it and some protest, however it makes them more confortable, just make sure there is a nice fluffy warm towel for them snuggle up in afterwards :-).
My hedgehog is very good and has a littertray placed beneath his wheel which he uses all the time, some hedgies will use a littertray and some won't, it just depends on the individual hog and they can be trained, as Igel wasn't litter trained when I got him, but he is very clean now.
Bathing
Some hogs like water and baths (my female loves it) and some don't, my male for example isn't fond of them. Some hogs annoint with anything they come across and often need a bath to rid them of whatever they have got stuck in their quills. Other hogs get itchy and dry skin so an aveeno oild bath may help with this.
It is good to give them a bath with aveeno oil in or baby oil, this stops their skin getting dry and itchy. I also use a tiny bit oj baby shampoo if my hogs have got something on them or stuck to their quills.
An oatmeal bath during quilling can sooth their skin, you run some warm water over a sock with oats in the end and put your hog in the water, you don't wash the "oat water" off of them. You have to make sure your hoggie is dried off completely as they can develop sores and get cold if not, I use 2 towels, both which are warmed in either the tumble dryer or on a radiator, the first dries them off and gets rid of most of the water and the second helps dry them even more. I always put their snuggle safe in after a bath too so if they are a little cold, they can go and warm up.
It is good to trim nails when they are in the water too as generally hogs will not ball up in the water and you can get to their feet easily, you can also see their quicks (red bit with vessels in) and this makes it easier to trim the nails without making them bleed.
An unusual habit
Some people may be quite alarmed when they get their hog home and it starts furiously chewing on something and then salivating excessively and spreading the saliva all over themselves. However this is quite normal behaviour, this very weird act is known as self annointing and is perfectly normal.
The picture below is of Igel self annointing on a cloth he found.


It is not know why they do this, all is known is that it is triggered by new or unusal smells. There are however a few thories......
- It may be a way to make a hedgehogs quills more toxic by spreading them with a nasty substance and hence evading predators, as in the wild they are quite resistant to poisonious plants.
- Some believe it is like a mating ritual to attract the opposite sex with smells.
- Others believe that it is an attempt - on the part of the hedgehog - to smell like other objects in its environment for purposes of self defense, the saliva will carry smells of the environment and allow the hog to blend in.
This act may have be associated with the belief that hedgehogs are commonly afflicted with rabies, they may have been confused with rabid animals that produce excessive frothy saliva.
[1] Quilling occurs between 8 and 12 weeks and again between 16 and 20 (ish) weeks depending on the individual hog. This is quite unpleasent for some hogs and other just seem to breeze through it. I found Igel suffered quite bad with it and a great remedy was a bath in oatmeal (put some oats in the end of a sock and place in the warm water which you will use to bath the hog). Another good product is baby oil or aveeno in the water when bathing them.