I have been running my Regency l1240 insert for 6 years now. I took out all the fire bricks cleaned and inspected the firebox with a good light. Everything check ok, no cracks, no holes, but looking at the fire bricks,I figured they lost some thickness so I changed them all. It is above 32 F today, so I will get a small fire to cure the bricks. I will see on the next cold snap if I can retain the heat of the stove for longer periods. I think these bricks were done , this stove works hard 6 months out of the year.