Subaru Forester 2005: Service intervals

I own a 2005 Subaru XT (Turbo) Forester that has done 90,000kms and is now out of warranty. Subaru indicate it should be serviced every 6 months or 12,000 km, whichever comes first. In the past I have always had the car serviced by Subaru as recommended, but I am now not driving many kilometers. The 6- month service is now due and I have only done 3000 km in that time. Is it imperative that I continue to get the car serviced every 6 months irrespective of the kilometres done, or would it be more prudent to have it serviced say every 5000 km irrespective of time?