In my experience Lodgers usually become jobless or subject to some other personal disaster at some point during the agreement and of course can't pay their rent. You, of course, being a regular decent person, don't throw them out immediately but cut them some slack. This ends up with them running up a large amount of arrears before they finally do a runner. So it is quite easy to actually end up making a loss.
Seems you've got to get as big a deposit as you can and be prepared to be a heartless wretch and throw them out immediately they get into trouble.
IMHO lodgers just ain't worth the hassle.
