ethandron....I would say that an average time factor is 6hrs. For example, Duck Legs are great after 4, but a kilo of gammon will be 6-to-7, or, depending on heat settings,could be 8hrs. I always cook on High for the first hr. before reducing to low and finishing-off with an hr. on medium; or even high if serving straight from the pot.
Please note that any skills which I have developed are as a result of advice from AB'ers who are experienced in the art of slow cooking. So my suggestion is that you and liverboys have a go with the slow cookers and, as I have done in the past, ask the questions that you want answered.
Thanks liverboys for your original question which has allowed me to chat, once again, with ethandron. I hope the replies from other AB'ers have been a help to you both.
Best wishes to you all.......Ron.
P.S. Try clicking below for more AB info on slow cookers.
http://www.theanswerbank.co.uk/Search/default. asp?SearchText=slow+cookers&searchType=site&x= 31&y=6