Been using them for a good few weeks with no problem as yet. I do not understand what people are doing to break them.
Two things did it for me.
Pushing the brush behind bushes close to windows. The hose gets caught and rips the back of the jet off. (This often broke the original black and red plastic fan jets as well). The capsules can be pushed back together but it’s fiddly. (Thankfully I don’t have many to do like that) I just had to adjust my approach to these windows
I’m also a Univalve user and using a Univalve requires that you leave a longer piece of pole hose between the top of the pole and the JG ‘T’ piece and also make sure it is held securely at the top of the pole, otherwise the jet hoses can pull on the back of the jets when you operate the valve. This is compounded if you use a swivel. I didn’t see the notes on the page when I bought mine and as a consequence kept pulling mine apart.
What worked for me was to lengthen the pole hose above the pole by 20mm and also the jet hoses by about 15mm. I’ve not had an issue since following this advice from Gardiner’s