Deep treatments might seem too much to use weekly, but you can use it monthly. You also may want to try to figure out what's causing the dry hair as well. Is the hair color-treated? Do you use a lot of heat styling (blow-drying, or curling irons and flat irons)? If these are likely causes, you may want to try to reduce the amount of heat you use and see if that doesn't help resolve the issue or at least make it easier to treat.
Can you tell me how to cure dry hair?
Dry hair needs a really good moisture shampoo, moisture conditioner and a once a week deep conditioning treatment!