10-15 minutes to get the original year for a whole collection?!!
Man, more often than not I spend that kind of time PER SONG!
IMO 'original year' is one of the most interesting but also most difficult fields to populate.
Sources I use, pretty much in order of importance:
1. allmusic (almost useless for music outside the anglo-saxon realm)
2. wikipedia (not always reliable)
3. google, used in several ways:
- searching for an artist's official homepage / a good fanpage and hoping for a biography or complete discography
- searching for lyrics
- searching for charts for that particular music genre
5. the Joel Whitburn chart book (or rather, one of the XLS files that circulate every now and then on alt.binaries.sounds.whitburn.pop)