My totals are extremely modest
Dream Theater - 3 times
Deftones - twice
65daysofstatic - twice
Anathema - twice (once was supporting Opeth)
Opeth - will be twice when I see them again in a few weeks. EDIT: Will actually be the third time I see them, forgot about the PN09 show with DT
Then there are a few bands I've seen once before that I'll maybe see again in the coming months - Tesseract, Mono, Mastodon.
Whether I go and see a band that I've seen before depends mainly on their most recent album and the potential setlist. eg. Maybeshewill - I'm not so keen on their latest album, so I probably won't go and see them on this tour.
DT I would probably always go and see, as long as they were playing close enough. I travelled a fair distance to see them earlier this year, but I would only do that again if I knew what the setlist was going to be and I liked it.