If I'm just going to the office for the day I use a small tray from the tackle box that will hold my back up eVic, 3 tanks, 3 - 10ml bottles of juice, 3 spare Kanger heads and a couple spare drip tips.
If I'm on the road visiting clients then I take the larger tray from a tackle box that will hold my back up eVic, 6 tanks, 6 - 10ml bottles of juice, 3 spare Kanger heads, 3 spare IkenVape cartos, 3 spare iClear 30S heads, Q-Tips for cleaning and a couple spare drip tips.
My primary eVic and current tank/flavor is in a pouch on a lanyard around my neck for instant access.