The average use years of bathroom, kitchen-units and toilet is not clear, though each is not long in comparison with that of house. But it is important to grasp those as the basis of maintaining and replacing such equipment. In this study, I estimated those by analyzing the data based on a questionnaire to about 4 thousands of the residents of detached houses in 5 suburban estates. Use years of bathroom averages 20-25 years, kitchen-units less than 25-30 years, toilet 15- more than 20 years. Moreover, those of bathroom and kitchen-units are extending in these 40 years. It is pointed out that there are some problems in this situation, because, for example, these average years are much longer than 10 years, which is the general holding period of replacement parts by manufacturers.