Things usually do - and at the worst possible moment.
After many mods done to my mountain bike as well as equipment, I've used each ride to perform test. Not only on the equipment but also the overall configuration.
I'd rather find a problem before leaving Johannesburg than experience it somewhere after leaving London.
WHAT TEETHING PROBLEMS HAVE I EXPERIENCED?
The bearings in the pedals were grinding (defective) and the pedals needed replacement.
Rear light bracket snapped and fell off - caused by bouncing down the side of a rather large hill on gravel track.
After a leaving at 4am, whilst still dark, the front light simply stopped in the middle of a bush track. Wire joints need soldering and not just crimping and taping - and a small head torch is also needed as a backup.
The rear panniers needed re-positioning backwards - away from the pedals to prevent fouling the pedal stroke
The charging circuitry stopped working - and after closer inspection, I found the USB Hub was unable to deliver correct amperage to the devices.
I was also able to isolate charging problems with my Samsung phone to a buffer battery being needed between phone and actual Dynamo Hub.
A friend suggested Rok Straps as a means of holding down my tent and sleeping bag to the top of the pannier racks - and these have proved to be a brilliant investment.
Unlike "normal" tie-down straps, these straps are elasticized on one side and prevent anything becoming loose after a long day riding.
I have had some amazing recommendations from the long-distance biking community in relation to equipment and planning.
Replacing my standard resin disk brakes with metal brakes that have fins to dissipate heat.
Joining www.warmshowers.org - I will maybe do a separate blog on this amazing website in the future.
Store items of clothing and equipment in separate waterproof bags. Removing anything from a bag during a storm won't cause everything to get wet.