Appliance cavities come at different heights and in different sizes. If you like to use your microwave as a second oven, make sure it can hold your Pyrex baking pans. A new range should be big enough inside to accommodate your favorite roasting pan—with plenty of head room for the turkey. (Not sure? Take a 20-pound bird with you when you go shopping.) Watch out for ranges with low-slung ovens (perhaps built that way to allow for a thick cooktop with fat designer knobs) and for front-loading washers pitched so low they require a pedestal (i.e., extra space) to save your aching back.