Well, correct me if im wrong, the difference between tempered and regular is what happens if it breaks.
That's one of the two main benefits, safety. The other is strength - tempered glass is
much stronger, which is especially important for things like shelves or where the glass might get some physical contact.
But the significant part of my question was the third major difference, though it's definitely not a benefit:
COST. The tempering process is done after the glass has been cut, beveled and polished and it's one of the most significant costs in the whole production process. The lack of tempering is possibly why your pricing beats IKEA's products at the moment - IKEA only sells tempered glass.
The one thing he told me was that tempered is the double cost compared to regular
Precisely, which is why when comparing oranges, your shouldn't be looking at apples.
but if i still go with larger doors it will be cheaper than ikea tbh.
Maybe, we'll see once you get the pricing. Previously most people have not been able to find good glass suppliers. I've been lucky and found a great one not too far from here, however for many things they still can't beat IKEA's prices on glass alone.
The only problem with putting the hinges on is that with tempered you have to be exactly accurate by the mm. Often special drills and etc.
You can't do anything to modify glass once it's tempered - unless you un-temper it first, but its probably cheaper just to get a new piece most times. All holes and other changes to glass shape must be done prior to the tempering process. mm precision is not necessary if you are using hardware that has adjustment potential. But big glass places can do mm precision as part of their regular process anyway because of the advanced machines they employ. Once you put a hole in a piece of glass, it doesn't matter if you temper it or not - you can't change the position of the hole.