Your budget is the primary factor in determining whether you sod or seed. If you can afford it, sod where you most need it and seed the other areas. Sod will become established more quickly and permit use of the area faster. Eliminate foot traffic and children?s play traffic on the newly sodded areas for 2 weeks, then allow only light traffic for 2 more weeks. If you sod and seed, get grass seed of a similar mix and type so your seeded and sodded areas eventually match. Time of year can also be a consideration. Cool-season lawns, such as bluegrass and fescue, are best seeded and established at the end of summer (late August and September in most of the country). Early spring is another favorable time to seed cool-season lawns. In midsummer to late fall, sodding usually provides better results. It?s difficult to keep seedlings evenly moist during the heat of summer, and if sown too late in the year they may not become well-enough established before freezing temperatures arrive to survive the rigors of winter. Warm-season grasses such as Bermudagrass, buffalograss, and zoysiagrass survive best when established in late spring or early summer.