It is advisable to have full-time help for at least the first 48 hours and someone to help with normal house duties for several weeks. I recommend no heavy lifting or exercise for the first 6 weeks. You cannot drive until you are off pain pills. If you have younger children some form of childcare is very advisable.
Great question and an important one in planning for surgery. The first week after surgery is the most difficult after a tummy tuck. Generally, you will have a drain in place and will be walking around slightly hunched over. You will need help getting in and out of bed. You also won't be able to drive anywhere as you likely will be taking pain medications. Beyond one week, it depends on what kind of help you need at home. If you have small children, you may need help longer because even though you will be feeling better after 1-2 weeks, you will have difficulty caring for them. Good luck!