Like many other people, I do a reasonable amount of travelling, and always wonder what I really need to take with me to cover all contingencies. I generally seem to carry too much, so I used OneNote to create a list of what I should be taking.

So - what do I consider to be a must to take with me? Here is my list.

1.  Laptop
2.  Laptop power cable and adaptor
   
3.  Travel Plug
   
4.  Power bank
5.  USB Hub complete with USB connectors, HDMI and ethernet slots
6.  Adapters - USB3 to USBC, USB3 to Micro USB, USB3 to Mini USB, USBC to USB3
7.  3-in-1 USB3 to Micro USB, USBC and lightning cable
8.  USB Card reader to read SD and Micro SD cards
9.  Various USB Drives, SD and Micro SD cards
10. Microsoft ARC Bluetooth mouse
11. Windows Installer on an 8gb USB drive
12. MiFi with roaming sim in it
13. Lightning to HDMI adapter
14. Apple watch charging cable
15. Apple fold 'flat' plug with USBC to USB3 connector
16. Spooly USB to Lightning cable
17. Air pods
18. USB clicker
19. Spare batteries for mouse

MOST of this is in a case from MyMemory which swallows most of the items above. The exceptions are the 'fold flat' plug and the travel plug which due to UK plugs design are too bulky. 

These are all items that can be carried in my hand luggage and the case is not too bulky.

I also ensure I have access to my backups. I backup weekly, with a daily incremental. This is backed up to my Synology NAS drive which I can access from anywhere. I also use Microsoft Synctoy to backup any changes in my source code on a nightly basis - again to my NAS drive. I use the 'ECHO' options, which only takes changes to my source code and copies those files. This is real 'belt and braces' as any source I am currently working on is on GitHub.