The fewer times you have to purchase or replace, the better your technology, while the best technology requires no ongoing purchases or replacements at all. Perhaps even good technologies such as portable stereos need parts such as CD-ROMs. DVD-players, for example, are not good technologies until DVD disks become widely available. Electric lights are not good technology if they require non-standard light bulbs. Programs which require complicated start-up routines are not as good as those which start with a single command.
Good technology is personalized.
One of the things that makes a telephone useful is that you have your own telephone number. In a similar manner, email is useful because you have your own email address. Bank machines would not be at all useful unless they opened your bank account and only your bank account. Some of the simplest technologies succeed because they are personalized. Personalized housing is made possible with personalized keys, another good technology.