For those who can’t be bothered looking up the difference between a double-slipped granny knot and a double-slipped reef knot, tie the first and second knots with different ends of the string on top (eg. right over left, then left over right). If you do it right it will hold, no need for a double knot.

As for earphones (does anyone even use those anymore?) push them into a small pouch, start from one end and work your way along, pull them out the same way (it’s quicker than it sounds).