It would be great if they had mentioned to do a 'service wash' on your machine first to get rid of all the detergent sludge (hottest wash possible with no contents, just a little bit of Vanish, vinegar, or soda). Plus to do the cleaning with a pure soap like Dreft or a technical version (like Techwash), remembering to rinse twice so as not to leave a hydrophilic detergent residue on the surface of the DWR (i.e. pointless to have a water-loving coating to your garment)
Would change one aspect & that is to get people to do a 'service wash' on their machine before washing/ reproofing with specialist solutions
If you read the instruction booklet that comes with the machine it is mentioned, but I have yet to meet a person who has read their machine's one! This means to do a 90 deg wash with no detergent in (after cleaning the draw - best using boiling water). If you must you can always add a little detergent additive (something like Vanish) or vinegar/ soda crystals. The main objective is to remove the detergent sludge (left over stuff like the stuff that accumulates in the rubber rand of the door)
A machine should have a service wash every 20 washes or so to keep it clean/ efficient/ running for longer
Some have suggested the reason why this is not promoted more heavily is that the sooner your machine goes wrong - the sooner it needs to be replaced...
By getting rid of the detergent leftovers you will allow the DWR revitalisation to happen better, plus give a better chance for those 30 deg wash cycles to actually clean effectively
This is the type of thing that us people at Wrap know, but it seems no one else does!