In the stadium? Not many. I haven't even been to the DSB stadium yet. I try to go to away matches near where I live as often as possible - provided there's no compulsory bus-combi cause I'm not going from Middelburg to Breda via Alkmaar I went to the Sparta game in Rotterdam 3 weeks ago for instance.
I'll go to some home games when I live the Hague (moving in a month's time or so hopefully).
To compensate I watch _every_ game on TV (I only use my Eredivisie live subscription to watch AZ actually lol - couldn't even be bothered to watch Ajax-Fey the other day).
For me it's Utrecht home games normally always, but every season I miss several... away games only when it's no buscombi or when we take the time for a ticket in the home stand, like Roda away in two weeks.
As for VVV, this season many away games because I want to 'complete' the Jupiler League... only AGOVV and the new Zwolle one to go now and I've got nothing else to do anyway on fridaynights at 8pm. Only one home game yet.
For the foreign teams, St. Pauli games in the west, and Athletic once or twice a season, although I want more.