first last Vs last, first names

Most occasions we use the format, first name last name. There are few places, particularly while writing, that the structure last name, first name is adapted. In good old days, most often the last name reflected the occupation of the person. We see many family names with Baker, Clerk, Smith etc. So, while entering names in the record, last name sorted list would list out folks as per the jobs they work on. That would be easy for some one to keep track of the records and call the right set of folks for duty.
Not sure about the above theory. This occurred at me while using the address book in my mobile. I try to store the occupation of the person first before his/her name, eg Elec Sekar, Taxi Gopal, Law Ganesh, CA Manikam etc.