Slings
Young Ivory Ornamentals usually eat more regularly because they are growing and moulting more often. Offer small prey to Poecilotheria subfusca in sensible portions and remove leftovers before they spoil.
If an Ivory Ornamental sling suddenly stops eating, premoult is one common explanation. Keep water available and do not keep adding live prey.
Juveniles
Juvenile Poecilotheria subfusca can normally take larger meals than slings, but the interval should still follow body condition rather than a fixed weekly rule.
If the abdomen of an Ivory Ornamental already looks very full, wait before feeding again. More food is not automatically better husbandry.
Adults
Adult Poecilotheria subfusca can go much longer between meals than fast-growing slings. Offer suitable prey, then let appetite and abdomen condition guide the next feed.
A large adult Ivory Ornamental does not need to eat simply because seven days have passed. A healthy tarantula can tolerate gaps that would be unusual for a mammal.
Premoult and fasting
When Poecilotheria subfusca appears to be in premoult, remove live feeders and stop offering more until after the moult and hardening period.
Food refusal in Ivory Ornamentals can also follow a rehouse or occur with mature males. Check the whole context before changing prey or feeding more often.
Simple records
Record feeds, refusals and moult dates for Poecilotheria subfusca if you keep several spiders. A short note is enough to show whether a long fast is unusual for that individual.
Those dates are more useful for an Ivory Ornamental than forcing every spider onto the same feeding calendar.