Think you need to change the Internet use to something along the lines of reasonable Internet use - you don't want to discover that he spends all his time online downloading lots of big files that mean you get stung with excessive use charges by your ISP that wipe out your profits.
Likewise can you put something in there about reasonable electricity use - you don't want to discover as my dh did that you get stung by a huge electric bill because inconsiderate other person on the house kept an expensive fan heater on full heat full time regardless of whether he was in the room or not because he always wanted it to be warm and cost for him regardless of the cost (he didn't have any money to pay for it so didn't care and expected the others to pay). Only difference was when he was in he would have the heater on full and the window open as that was how he liked it when he was there.
I'd also think of any other things where you might want to stick in reasonable type clauses so you have something to fall back on if there are any problems, so:
keeping the kitchen tidy and not leaving unwashed dishes etc.
Space in the fridge.
Frequency of washing or times when it is good/bad to use the machine - you don't want to do an urgent wash only to find his wash just started.
Reserve the right to access his room if you think there might be a problem - be it a fire from smoking or candles or nasty smells.
Access to bathroom times if there's likely to be a busy time - you don't want to discover he or you has just run a nice soaky bath and other person needs to get in quick for shower before work. Or that they have used all the hot water having a 30 minute shower.
Ban drugs on the premises - even if you don't mind him smoking the odd joint or whatever if there's a problem down the line you can show that they are nothing to do with you.
Can you get hold of one of those energy monitors and see if your energy usage goes up significantly with him there, in which case reserve the right to add another fiver or whatever onto the bill for additional utilities used.
Does he need to have his own insurance or is he covered on yours? And are you still covered on yours with a lodger?
Anything about guests, noise levels etc...
And about sticking things to Walls or painting or moving furniture around?
Sorry if this all sounds negative but it's to try to make sure that you cover yourself, most of the time there shouldn't be a problem.
And excuse hasty list, I should be asleep by now!