Varies a lot, juice to juice, gear to gear, day to day.
I've been through 5ml in a day, but never a "normal" day.
Usually, I go through 1ml (busy day, on the go) to 3ml (lazy day, lotta time at my desk). To go past 3ml, I need an evening drinking with friends. (Heck, even with strangers. But I vape more in the pub than anywhere else.)
So a 5ml bottle might get me through a week, though it probably won't.
Or I might get through it on a Friday, though I usually don't.
It's variable- like when I was smoking. Might smoke 5-10 cigs a day, for days, then go through a pack and a half in the pub one late night.
You sort of need to work out how long it lasts you, so you can stock for it. But we're all very different.
Best,
Ande