I am spread out over southwest Montana so I file by town or city, then file by street, then number. I add year at the end. My file label adds the form used because I use an assistant and this helps with info gathering etc. The file number on the top of the report has 8 characters. The street name is abbreviated to be able to include all of the street number.
So 123 Elm Street Anaconda done in 2003 on a 1004 would be AELM1233. Then on the top of the file folder I show AELM1233/1004. The address is the only part of the job that is unmovable so to speak. I can quickly find out if I did the property before and when. If someone calls on the phone, I just need the address and can go to my software and zero in on the file by address. The file number also tells me when I did it. Since many persons are re-re-re-financing, I am doing repeat jobs and my file system takes that into account by putting the year done in the report. If towns have the same letter I revert to using the second letter of the town or giving the town a unique combination. so Deer Lodge and Dillon are DL and DI, Boulder, Butte (my primary market) and Bozeman are BO, B and BZ. If the same property is done in the same year, an A goes in preceeding the year thusly BEL123A3 for the second appraisal done at 123 ELM.
Each file has a 4X6 tag and each time the file is worked, photos added etc. it is marked with what happens to it. I do this because an assistant sets up the file, adds flood maps, types in comps etc. I staple this tag on the file for in five years or when the fle goes into dead storage , I will rip the tag off and reuse the file now having a clean file. Having the year at the top of the files guides file storage.
Works for me and that is the point. Every file system is ok if it works into your own way of doing things.