how often (if at all) does fireplace/stove glass break?

When I was at the fireplace shop the other week, the owner was saying that he has this customer who calls quite frequently needing replacement glass for his stove. His wife says it's his fault every time because he over loads it with wood and for some reason thinks it makes sense to move the wood with the glass door.

To directly answer your question, I don't think you should worry about the glass breaking unless there is some sort of user error.

I am pretty sure BKVP mentioned in the last couple seasons that in his time at bk they have never had a piece of glass break from a rolling burning piece of wood, but every winter a few guys try to use the door glass to shove wood deeper into the stove

Every once in a while here at hearth.com we hear of someone who has broken the "glass" in the woodstove . . . most, not all, seem to be when they cram in wood and slam the door shut or when they are taking a poker and boink the glass just right -- or just wrong if you would (some of them are a bit sheepish about this and figure it's a lesson learned the hard way.)

As mentioned, generally, the "glass" (most are actually a ceramic, such as neoceram) is pretty tough stuff that can withstand the occasional split that rolls up against it while burning.

I have broken glass by accident, threw a split in the fire and pushed it in with the door, when't to rake the coals one morning - late for work - door was still closed, was really late for work after that Then the wife was loading one night, closed on door and tried to put another split through the glass. So it happens

The pyrex type glass used years ago was prone to shatter when stressed and could break under extreme temperature shock. The newer transparent ceramics used now may crack if impacted, but not shatter, are much stronger and tougher, and can not be broken by temperature shock. Viewing windows have gotten larger (and safer) with the newer stoves.

Stove ceramic glass is strong, just don't close the door on splits, decorative fireplace glass doors are weak, tempered glass, biggest failure with those are when people burn the fireplace hot with the doors closed.

I was given a Nectre Bakers Oven (Australia) by a friend and the glass in the lower box had a crack that has been poorly repaired with some sort of sealant. I'm having it replaced before installing it in my son's cabin next month. The painful part was the cost. Over US$200 for that one small piece of glass! I'm just glad the stove was free!

If the glass breaks chances are the guilty party will be there to take action.