slow cooker

[bednobs]

i am thinking about buying a slow cooker. There seems to be a choice between 3.5 lts and 6.5 lts. If i got the larger one, do they have to be filled right up to cook in them? Do you have any idea if you culd cook a meal for 4 in the smaller one? and lastly, has anyones ever blown up? I get a bit edgy abou leaving appliances on hwen im out after my washing machine caught fire