Why It's Better to Seed a Lawn

Sod or seed? One costs a lot but looks great instantly, while the other is very inexpensive but takes a couple years to look nice - but which does better over the long run, and why?

I bought my current home in 2011. It had no lawn when we moved in - just dirt. To achieve immediate results we had front lawn covered with sod, which was fairly costly despite the fact that it is only about 1,000 sq ft (~93m²). The rest of the property (much larger area) was seeded with grass, which was WAAAY cheaper than the sod - I think it only cost $40 for two bags of seed. In the first year, the front lawn looked beautiful, and the rest of the property looked like something from a Mad Max movie. In the second year the front lawn still looked great, but had the odd weed - and the rest of the property still looked pretty sad. I think I may even have bought another $20 bag of seed and re-seeded the whole thing. By the end of the third year the front lawn was covered in weeds, the rest of the property was beautiful and green, with a few weeds here and there. Now, twelve years later, the front lawn is more weed than grass, and the rest of the property is still beautiful and green, with a few weeds here and there.

Here’s my front lawn - covered in dandelions and other weeds!

What the heck happened? Why did the sod turn to weeds? Why did the seeded lawn do so well?