Bands you have seen more than once separated by (very) long spans of time

Next month I'll have an opportunity to see Clan of Xymox, almost 31 years since I first saw them touring for Medusa in '87. I haven't much cared for anything they've done in well over 25 years though, so will likely skip it.

Longest span I can think of is New Model Army in '89 and '09. Fantastic both times.

King Crimson in 1974 and last year. They were awfully good both times!