How to weave in the ends

just finished a scarf – yarn is 40% merino wool & 60% acrylic.
What’s the best way to weave in the yarn (beginning & ending yarn & where I joined skeins) – best to use a crochet hook or a tapestry
needle ? Do I weave up & back down along the edge of scarf ?
How many inches do I need to weave in ? thanks for any help

I use a crochet hook which doesn’t need as long a tail as using a tapestry needle which most people prefer, it’s just easier for me to use the hook. The Duplicate stitch join video shows how to weave in ends by following or duplicating, the sts already knit.