One of the factors which may have influenced day hospital expansion is that day hospital treatment was earlier found to be cheaper than in-patient treatment, as some of the ‘hotel’ costs were avoided. The increasing price of ambulance transport has reduced this advantage. Further reduction occurs if the expenses of keeping a patient at home (community services, share of housing, etc.) are set against in-patient costs. Using such detailed comparisons, treatment up to twice weekly at a Day Hospital provides good value for money, but more frequent treatments can prove costlier than in-patient or residential care. Realistic attempts are now being made to cost a complete course of treatment, for example three months' visits to a day hospital. Depending on whether this is regarded as equivalent to 15 or 10 weeks as an in-patient, the relative cost of day hospital treatment is 32–90% of in-patient costs. ‘Throughput’ is as vital to day hospitals as to wards, and the average number of visits for day hospital treatment has decreased over the years from 40–20, and the recommended size from 50 to 30 places. Critics of comparisons between in-patient and day patient treatment emphasize that we are not comparing like with like. Day hospital treatment relates more closely to independence and accords with the preferred wishes of most patients and families. Costing involves not only money but staffing and here the day hospital continues to show advantage. Not only can day hospitals attract nurses and (scarce) therapists, but a nurse can maintain ten times as many patients in the day hospital as she can in the wards. Over ⅘ of day hospital patients have help at home from a chief carer (member of family, neighbour, friend, Home Help, etc.). These helpers increase greatly the number available to care for the old at home and this is the most vital factor in the comparison of costs between day hospital and in-patient care.