It developed a leak after 12 years due to extensive rust... of course, it had been forgotten on the rooftop without even a single maintenance!!! Of course, I had also installed an expansion tank in the collector circuit so that it wouldn't be strained by the increased pressures during heatwaves.
Up until now, its performance was excellent even with a little cloudiness; if I had done the maintenance, maybe it would still be working!
Searching to buy the next one and reading user reviews from other companies, I see an average lifespan of 5 years with maintenance, and as soon as the warranty ends, they develop leaks... maybe I was lucky!
I will buy the same one again, hoping the company hasn't compromised on the quality of the materials.