Assuming the studs are 16 inches... I just helped redo a friend's sunroom that had some water damage, rip out the drywall and find the studs are about 30 inches apart... Nice...
You can go 24" o.c for interior non-load bearing walls, but it causes issues with nailing and drywall thickness.
30" is extreme and would imagine it was done out of permit and by a novice. That would not make for a fun way to hang anything, drwayll, sheathing, pictures. Bummer deal.