I must be the dimmest DIYer...
Moved into seven-year-old house recently. After the initial settling in period, noticed that the bathroom shower dripped for an hour after being used, traced to water dripping off the hose. This was in turn traced to perished seals at each end. ITMT the en-suite shower head kept falling out of the holder. As it's a heavy Triton shower-head, this could cause some discomfort to Senior Management, the only one allowed to use the en-suite.
Wandering out to the garage (just under a hundred crates of stuff) I found a spare new hose and some washers. I replaced the ensuite hose with the new one, and put new washers on the bathroom one. The original hoses were quite stiff, so probably past their best.
So far, so good: bathroom hose doesn't drip, and ensuite shower head doesn't fall out of holder. Make a resolution to get two new hoses next time I'm in B&Q.
Return from B&Q with one genuine Triton hose, because a) they only had one, and b) the prices were much the same for all the hoses. Fit new hose to ensuite. Shower head falls out of holder. Replace hose with the original replacement, fit Triton hose to bathroom shower, head falls out of holder. Replace hose again.
Look very carefully at Triton hose: two truncated cone-shaped endings having a slim O-ring seal about mid-way. On placing them together and looking very closely, one cone has a very slightly smaller diameter for the same angle of taper - and the difference is hard to spot.
Replace ensuite hose with new Triton hose (again) ensuring smaller diameter cone is at the holder end. Shower head sits perfectly in the holder, so doesn't fall out.
I look at the blurb that came with the hose (not much), it doesn't say anything about which end is which. I check the original fitting instructions for the shower, similarly silent on the subject.
The only clue that the two ends are different is one cone has two spanner flats on it. This end fits in the holder.
Given the 50-50 nature of getting the hose fitted the right way round, there must be millions of shower-heads that regularly clout the showerer as they fall out of the holder - or does everyone but me realise that the two apparently-same ends of the hose are, in fact, crucially different?
I hope this helps someone else to avoid this issue.
TF