All fittings will wear, talking to the Rectus rep recently and he could not believe the life cycle of our fittings. Up to 100 connections/disconnections a day, 5 days a week, 48 weeks a year. Dragging them along the ground, getting grit in them. He reckoned that window cleaning must be the toughest enviroment for any type of fitting.
Using some kind of connection protection (Protecta-Ball etc) on both sides of the fitting is a sure way to reduce problems and increase length of fitting life.
Hozelock fittings are just not reliable enough for professional use, I tried to use them for 2 years and they always led to problems.
Rectus fittings are great, but are still prone to wear. Make sure that if using Rectus fittings they are genuine as there are a lot of Chinese/Korean replicas on the market that are simply rubbish. They will collapse after just weeks of use.
We are constantly trialling new types of fittings and keep coming back to EZ-Snap (rectus) type fittings.
The Pro series fittings (19) are also very good, but we tend to use these for non-pole type connections. Connecting tanks together, 1/2" hose to professional hose reels etc. We are selling more of the high-end hose reels now and these have 1/2" female ports which the Pro series screw into and allow reliable, leak free, robust connections to.