Question
I have large lawns but tey are covered in bare patches. I left them over winter but no improvement. Some have a little moss but most are just bare.

Answer
It sounds like shade is a problem on your lawn.

Grass grow best in full sun, but can grow in shade with some special care.

rake moss and loosen the top of the soil. spread grass seeds and keep the top 1" of soil consistently moist (by watering daily for 2-3 weeks) until the new grass sprouts.

You may have to re-seed annually in the heavily shaded areas.

In sunny and partially sunny areas, you should be able to get grass to grow and come back year after year. Just make sure you loosen the top of the soil before seeding to ensure good soil/seed contact. A de-thatcher (verticutter) is a good machine to rent for this purpose. it slices the surface of the soil preparring it for seeds.

Make sure you water frequently, and shallowly until grass sprouts. then increase the amount of water you apply and the time between waterings. the goal after 4-6 weeks is to be watering infrequently, but heavily, such as once per week for 2 hours rather than the daily applications.