With 13 or 14 nights, I would definitely split. I, personally, get antsy after about a week and need to switch up my environment! We've always done splits based on location and typically do MK/EP resort splits and plan our park touring accordingly (only going to MK and maybe AK while at the MK resort and only going to DHS/EP when at the EP resort). We do base it on budget, but we only stay deluxe at this point (we've done mods and values and it's just not our thing). We only go if we get a good discount and, though we have favorites, will pick based on price. For example, I will price out Swan/Dolphin, BC/YC and BWI for an EP resort stay (of course, factoring in transportation and resort fees into Swan/Dolphin stays). We prefer BWI, but if there is a substantial price difference, I certainly don't mind staying in a different EP resort. Same with the MK resorts. Whatever is cheapest (usually WL). I would also consider a AKL in a split, but I honestly don't know if I could do a week there! (We've done 3 night stays). I really like having close access to other resorts and parks as part of our resort stay. This is why, if I were going to consider a mod, I would probably only consider POR and POFQ (possibly Ft. W, but with a golf cart) simply because of the boat access to DS (plus they are lovely resorts!). I also don't mind pricing out studios and villas vs. regular rooms to see where I can get the best deal. So for us, it's really price and location.