Most car insurance repairs use ‘genuine’ parts.
Not been my experience... especially where AutoGlass are concerned. At least with Axa.
I had a stone chip September 2022... called AutoGlass, due to location, had to be a replacement not repair. Told AutoGlass I wanted a genuine part (or at least a Pilkington part, as per OEM). They said it's up to Axa... Called Axa... phone system sends you right to Autoglass when you press that number. "Speak to Axa". Called Axa... mentioned the issue "Oh, you need to speak to windscreens .. let me put you through.." ... "Welcome to AutoGlass" ... Eventually someone at Axa told me they've noted it and I'll hear back within a couple of days.. two weeks passed. Called Axa for an update... same hassle getting through, got through to someone who wasn't able to advise or even tell me who I was speaking to the first time. Seemingly no hope of a call back to say "Yes, we'll use the genuine part" and the weeks were rolling on. AutoGlass kept calling me asking to book in off the back of the usual process, eventually I accepted and went down as I was scared of getting pulled over for it, the crack was getting bigger and bigger.
Had to go to the fitting centre as that car had radar / city brake too. The AutoGlass guy laughed at me saying I'd like a genuine part... "Toyota don't make glass".. "Our stuff is sometimes better" - the usual spiel. Anyway, he fitted some no name brand, lacked the little 'ear' logo for acoustic tuning. Had distortion that you'd spot on a smooth motorway as well, the 'grain' of the road looked like it was spilling over it, right from the drivers view. Also bad condensation (this was around November time too) inside the glass all the time unless A/C was on. I changed the cabin filter thinking it was done. No change. The top of the glass was also half a centimetre 'up', very noticeable when washing the car. The lane keep warning was also way off kilter! As usual, I stopped, said nothing and lived with it for a few weeks... in case it was just 'in my head' and I was splitting hairs. But eventually got fed up.
AutoGlass customer service is abysmal. So basically, you complain they offer an opportunity to refit - but refused to use a decent part. I told them I was unsure if the technician fitted the part wrong, or if it was just such a poor quality part that it didn't fit properly. Then they offered half of my excess back (£35) as a final offer, after that, they ignored my emails and calls. Their procedure points you to make a complaint to the Financial Ombudsman, but if you do that, the Financial Ombudsman complaint form specifically informs you that they can only help with disputes between you and financial organisations / processes (e.g. finance and the likes)... Absolutely no use. How that company can continue to publish that as it's "Still not happy" route is beyond me, my guess is 99% of customers don't care enough.
Eventually I had to speak to Axa, in a branch - something I rarely do as most things can be done online or with a call. A woman there took personal responsibility for it and as a result of the hassle, had agreed to source a Pilkington panel which took no time at all. They told me I had to let AutoGlass fix it at their centre though. Went down.. same guy... but he was surprisingly friendly / apologetic for the experience. New panel, fitted perfectly, no condensation, programming of the radar / lane keep was perfect (more accurate than when I bought the car even) and it was quiet inside again, crystal clear optics.
OEM parts definitely are worth the premium in price. I wish more insurance would use it. They seem to do everything cheap in my experience and usually when you ask for genuine, they charge you for it and it's silly prices. I tried everything before my resolution came... Even trying to source a panel myself via Toyota who could do it for around £350 ish (non heated) but said they usually will fit it, but who did they get on site to do it? ...AutoGlass. Nobody else. Who has to take it to their local centre for the sensor calibration? ..AutoGlass. IF I was to order the glass in, they'd let me take it, but other centres told me they wouldn't risk fitting glass they didn't order / bring as mishandling could make it too likely to crack etc. The price of getting my own part fitted and programmed (if I ordered it from Toyota, right to the other fitters warehouse) was around £900 all in!
Needless to say... when I changed my car in January this year, the lack of fancy sensors and safety tech was a breath of fresh air! Not missing it at all, as cool of a party trick as it was on the car. It's not worth the hassle in my view. Not with the standard of repairs / maintenance of these things into ownership.
I got so many stone chips, and a few windscreens on my 2005 Panda - but back then I'd be on many B-roads daily, and here the farmers / road service keep these little 'stacks' of road stones / pebbles periodically along the way - not sure why, but they blow off or get hit, and leave fresh stones like marbles across the road, ready to be flicked up at a moments notice. The Panda was quite tall and steep at the front, relative to a lot of other cars, which I felt made it particularly prone to getting chips. I miss the simplicity as they could repair, or fully replace it right on my street. Never had OEM parts for the Panda, but then I never had one on it when I got it either so I didn't know what the sound insulation or clarify of a factory part was versus el-cheapo glass. Plus, it was much much older and I was much-more-broke.
Tl;dr - Genuine parts are far superior, go into a branch if you need someone to take ownership of sourcing them via insurance!