Unit Portables is a compact shoulder back can detach and reattach its storage elements. This way you can take what you want with you and nothing that you don't, and easily swap pouches in and out for easy customisability.
Pouches attach and detach with a series of snapping buttons so you don't have to worry about anything suddenly falling off all by itself, plus the top closes to keep your laptop secure. The bags come in several colours and can accommodate either a 13-inch or 15-inch laptop (depending on the size you choose). You can also add an iPad sleeve if you want. The bag isn't the cheapest around, but the swappable pouches can make it easy to keep one bag and simply exchange what you need at a moment's notice.
Unit Portables isn't the only transformable bag we've featured. The UNDFND One Bag is another great option geared towards photographers.
Unit Portables (€79/$99 - €99/$124)