We do alot of residential homes and they always seem to be keen to get the price down a bit, prob because for them its an on going process as soon as your done then they need doing again.
we normally quote normal price but less 25% if they agree a regular contract, which normally works.
They would usually expect you to be respectful of the residents which means working around people and lots of furniture and belongings etc.
Odour removal is normally the biggest issue, so would need something very effective to keep them as a customer.
Also as mentioned drying time as its difficult to keep them off

steve