A lot depends on what you want to do. We've had several days where we started in DL at rope drop at 8am, then took a long afternoon break, then finished the night in DCA. Mornings were easy. Lines are shorter and FP are generally available for whatever you want. Then about 10:30 I would start checking the app for RSR return times. Those run out quickly and we wanted an evening time. Once a time was available that worked for us I got a FP. This was on average around 11:30-12:00 that I got the RSR FP. At that point we were locked out of a new FP for 90 minutes, but we would usually have some other FP banked up to use at DL or we were ready for lunch and a break. Then, while at the hotel I would check 90 minutes later to see if there was another FP available for evening. Most took a lot longer to run out, but by getting the ones that run out first, I was able to stack up to 5 in the evening/night hours when we came back.