It's a little bit of both. Either way, it's the swap board, PDs, Swap w/pot, then IVDs/APD as a last resort. One month last summer, I was able to PD my entire schedule and we still had a SSapalooza. It's weird like that sometimes. You don't need great coverage, just close coverage and a little flexibility.

Thankfully, starting this year, weekends are just another day in my house. In fact, we prefer to do stuff during the week when it's quiet.