@Melissa - we had seller credits AND seller repairs. The seller had a faulty Federal Pacific electrical box (they are known to catch fire) that we demanded that they replace. (It was the main electric box. It involved the seller calling the electric company and having them pull the meter so the electrician could change the panel. I knew this since my father was an electrical contractor.) There was mold in the attic that we had them hire a remediation company for and show written proof it was taken care of. Then there was minor plumbing and electrical that all added up (house sat unoccupied so the fixtures all leaked and didn't have shut off and no GFCI plugs in wet areas), plus two windows where the seals were shot. We asked for seller credits on those since we planned on changing out all of the windows anyway and wanted them to match.
My advice is that when you get a home inspection (not IF, when), if issues pop up send the entire inspection report over to the seller. We were able to use it as a bargaining tool and say "if you take care of this, we'll deal with that. You don't have to deal with the windows, just give us a credit. We'll take care of the GFCI issues and plumbing issues." It also shows that you're reasonable. I didn't ask for them to do all the work. If you go with a government loan (FHA or VA), the inspection report stays with the property for six months, which is another incentive for the seller to get the house sold and take care of repairs.