For our Nano Tip, Stick Tip, and Nail Tip hair extensions we would recommend 8 packs for a full head and 4 packs for half a head. Each pack includes 20 strands.
For our Tape hair extensions, we would recommend 5-6 packs for a full head and 3 packs for half a head. Each pack includes 10 strands to create 5 sandwiches.
For our Weft hair extensions, we would recommend 1 weft for a full head.
We have some articles on our website that go into further detail about this that we think you may find useful -