Depending on the size of area that is damaged some home owners prefer to sod an area where others may just use grass seed to fill in the bare spots. Most will seed their lawn in the Spring & Fall to repair the damage, after 3 or 4 years of nematodes & over seeding each season you will improve the health & overall appearance. If you have grubs in your lawn there is no amount of money that you can spend on grass seed and fertilizers that will grow you a beautiful lawn unless you apply nematodes because they feed on grass roots and you will just continue to feed grubs and never see improvements in your lawn.