This is a common question at this time of year; the answer to which is likely determined by your individual circumstances, where you live and how much you are willing to spend. As is usually the case, there are benefits and disadvantages to both methods.
Spreading grass seed is a lot easier and less expensive than laying down sod. If you live in a climate that is hot in the summer but has cold winters, planting seed might be the best option for your lawn. But, don’t just spread your seed and forget about it. Seed needs to be kept moist while it germinates; you may even need to re-seed in some spots. There does need to be some soil preparation in both methods, such as raking and weed removal.
The great payoff about sod, of course, is the “instant” beautiful lawn factor. In this age of instant gratification, who doesn’t want that? However, constant maintenance is required after sod installation to keep it watered until its root system is established and to ensure that no fungal diseases become evident. Sod is more expensive than seed and should be installed on the same day that it is freshly cut. In fact, be cautious about buying squares of sod from your local home improvement center, as it may have been cut several days before.
Your sod will look better if you have your local landscaping professional install it for you. They may also have a connection to purchasing the best sod at an affordable rate. You could possibly reduce your installation fee by performing some of the physical labor yourself. The cost of seed, sod and installation will vary according to your location and the current market. Sod grows well in all climates.